Lithocholic acid-based oligomers as drug delivery candidates targeting model of lipid raft

This study presents a new approach to designing a lithocholic acid functionalized oligomer (OLithocholicAA-X) that can be used as a drug carrier with additional, beneficial activity. Namely, this novel oligomer can incorporate an anti-cancer drug due to the application of an effective backbone as its component (lithocholic acid) alone is known to have anticancer activity. The oligomer was synthesized and characterized in detail by nuclear magnetic resonance, attenuated total reflectance Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, thermal analysis, and mass spectrometry analysis. We selected lipid rafts as potential drug carrier-membrane binding sites. In this respect, we investigated the effects of OLithocholicAA-X on model lipid raft of normal and altered composition, containing an increased amount of cholesterol (Chol) or sphingomyelin (SM), using Langmuir monolayers and liposomes. The surface topography of the studied monolayers was additionally investigated by atomic force microscopy (AFM). The obtained results showed that the investigated oligomer has affinity for a system that mimics a normal lipid raft (SM:Chol 2:1). On the other hand, for systems with an excess of SM or Chol, thermodynamically unfavorable fluidization of the films occurs. Moreover, AFM topographies showed that the amount of SM determines the bioavailability of the oligomer, causing fragmentation of its lattice.

Enzyme-linked immunosorbent assay (ELISA) for the anthropogenic marker isolithocholic acid in water

Bile acids are promising chemical markers to assess the pollution of water samples with fecal material. This study describes the optimization and validation of a direct competitive enzyme-linked immunosorbent assay for the bile acid isolithocholic acid (ILA). The quantification range of the optimized assay was between 0.09 and 15 μg/L. The assay was applied to environmental water samples. Most studies until now were focused on bile acid fractions in the particulate phase of water samples. In order to avoid tedious sample preparation, we undertook to evaluate the dynamics and significance of ILA levels in the aqueous phase. Very low concentrations in tap and surface water samples made a pre-concentration step necessary for this matrix as well as for wastewater treatment plant (WWTP) effluent. Mean recoveries for spiked water samples were between 97% and 109% for tap water and WWTP influent samples and between 102% and 136% for WWTP effluent samples. 90th percentiles of intra-plate and inter-plate coefficients of variation were below 10% for influents and below 20% for effluents and surface water. ILA concentrations were quantified in the range of 33-72 μg/L in influent, 21-49 ng/L in effluent and 18-48 ng/L in surface water samples. During wastewater treatment the ILA levels were reduced by more than 99%. ILA concentrations of influents determined by ELISA and LC-MS/MS were in good agreement. However, findings in LC-ELISA experiments suggest that the true ILA levels in concentrated samples are lower due to interfering effects of matrix compounds and/or cross-reactants. Yet, the ELISA will be a valuable tool for the performance check and comparison of WWTPs and the localization of fecal matter input into surface waters.

Profiling of bile acids in bovine follicular fluid by fused-core-LC-MS/MS

Bile acids (BAs) are present in follicular fluid (FF) from humans and cattle. This fact has triggered an interest on the role BAs might play in folliculogenesis and their possible association with fertility. To achieve a better understanding about this subject, new methods are needed to provide reliable information about concentrations of the most important BAs in FF. In this context, liquid chromatography-tandem mass spectrometry (LC-MS/MS) offers high specificity with a relatively simple sample workup. We developed and validated a new assay for the quick profiling of the 9 most abundant BAs in follicular fluid from cattle. The method uses 200μl of FF and can quantify cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA) and their glycine (G) and taurine (T) conjugates. Lithocholic acid (LCA), its conjugates GLCA and TLCA, and sulfated forms, were present in some samples, but their concentration was low compared to other BAs (in average, below 60ng/ml for LCA, GLCA or TLCA and below 20ng/ml for their corresponding sulfates). Method performance was studied at three quality controls for each compound in consonance with their physiological concentration. Excellent linearity and recovery were found for all compounds at every control level. Intra-day and between-day precisions (%CV) and accuracies (relative errors) were below 15% for all the compounds. Matrix effects were negligible for most of the analytes. Samples undergoing freeze-thaw showed no degradation of their BAs. The method makes use of a fused-core phenyl column coupled to a triple quadrupole tandem mass spectrometer to achieve chromatographic separation within 5min. We quantified BAs grouped in four different follicle sizes (3-5mm, 6-8mm, 9-14mm, >15mm), obtaining a similar relative BA profile for all the sizes, with CA always in higher concentration, ranging between 1600 and 18000ng/ml, approximately, followed by its conjugate glycocholic acid, GCA, which ranged between 800 and 9000ng/ml. The highest concentration in CA, DCA or CDCA was always detected in FF stemming from follicles of 6-8mm. To our knowledge, this is the first report in which BAs subspecies have been detected and quantified in bovine follicular fluid.

Consumption of some polyphenols reduces fecal deoxycholic acid and lithocholic acid, the secondary bile acids of risk factors of colon cancer

This study was performed to examine the effect of dietary polyphenols on fecal secondary bile acids, such as deoxycholic acid and lithocholic acid, the risk factors of colon cancer, in rats fed a high-fat diet. In experiment 1, rats were fed a 30% beef tallow diet containing 0.5% polyphenols for 3 weeks. Dietary curcumin and caffeic acid significantly reduced the fecal concentration of deoxycholic acid. Dietary caffeic acid, catechin, rutin, and ellagic acid significantly reduced fecal lithocholic acid. Fecal hyodeoxycholic acid, a metabolite of lithocholic acid, was markedly lowered by dietary curcumin, caffeic acid, catechin, and rutin. In experiment 2, rats were fed a 30 or 5% beef tallow diet with or without the addition of 0.5% curcumin. In the rats without receiving curcumin, the fecal level of deoxycholic acid was significantly higher in the high-fat diet group than in the low-fat diet group. Fecal deoxycholic acid was significantly reduced by dietary curcumin in the high-fat diets but not in the low-fat diets. The results suggest novel effects of some polyphenols favorable for colon health by reducing secondary bile acids in animals fed a high-fat diet.

Human cecal bile acids: concentration and spectrum

To obtain information on the concentration and spectrum of bile acids in human cecal content, samples were obtained from 19 persons who had died an unnatural death from causes such as trauma, homicide, suicide, or drug overdose. Bile acid concentration was measured via an enzymatic assay for 3alpha-hydroxy bile acids; bile acid classes were determined by electrospray ionization mass spectrometry and individual bile acids by gas chromatography mass spectrometry and liquid chromatography mass spectrometry. The 3alpha-hydroxy bile acid concentration (mumol bile acid/ml cecal content) was 0.4 +/- 0.2 mM (mean +/- SD); the total 3-hydroxy bile acid concentration was 0.6 +/- 0.3 mM. The aqueous concentration of bile acids (supernatant after centrifugation) was identical, indicating that most bile acids were in solution. By liquid chromatography mass spectrometry, bile acids were mostly in unconjugated form (90 +/- 9%, mean +/- SD); sulfated, nonamidated bile acids were 7 +/- 5%, and nonsulfated amidated bile acids (glycine or taurine conjugates) were 3 +/- 7%. By gas chromatography mass spectrometry, 10 bile acids were identified: deoxycholic (34 +/- 16%), lithocholic (26 +/- 10%), and ursodeoxycholic (6 +/- 9), as well as their primary bile acid precursors cholic (6 +/- 9%) and chenodeoxycholic acid (7 +/- 8%). In addition, 3beta-hydroxy derivatives of some or all of these bile acids were present and averaged 27 +/- 18% of total bile acids, indicating that 3beta-hydroxy bile acids are normal constituents of cecal content. In the human cecum, deconjugation and dehydroxylation of bile acids are nearly complete, resulting in most bile acids being in unconjugated form at submicellar and subsecretory concentrations.

Effect of tartaric acid and dietary fibre from sun-dried raisins on colonic function and on bile acid and volatile fatty acid excretion in healthy adults

Sun-dried raisins are a source of dietary fibre and tartaric acid. The effects of tartaric acid on colon function have not been the focus of extensive research. The purpose of the present study was to evaluate the effects of dietary fibre and tartaric acid from sun-dried raisins on colon function and on faecal bile acid and short-chain fatty acid (SCFA) excretion in healthy adults. Thirteen healthy subjects were fed 120 g sun-dried raisins/d or 5 g cream of tartar (equivalent to the tartaric acid in 120 g sun-dried raisins)/d for 9 weeks, divided into 3-week cycles. The experimental diets were fed in a crossover design after an initial control period. Faeces were collected for the last 4 d of each cycle for analysis of SCFA and bile acids. Intestinal transit time decreased from 42 h on the baseline diet to 31 h on cream of tartar (P<0.1) and to 28 h on sun-dried raisins (P<0.05). Faeces were softer on both sun-dried raisins and cream of tartar, but sun-dried raisins increased faecal wet weight (P<0.05), while cream of tartar did not. Sun-dried raisins caused significant reductions from baseline values in total bile acid concentration (from 1.42 (SD 1.03) to 1.09 (SD 0.76) mg/g, P<0.05), whereas cream of tartar did not (1.40 (SD 1.06) mg/g). Sun-dried raisins also significantly reduced the lithocholic (LC):deoxylithocholic acid (DC) ratio (from 1.63 (SD 0.85) to 1.09 (SD 0.50), P<0.02), whereas cream of tartar reduced the ratio, but to a lesser extent (1.29 (SD 0.79), NS). Both faecal bile acids and the LC:DC ratio are indicators of reduced risk for colon cancer. Sun-dried raisins increased total SCFA excretion (from 5.6 (SD 3.4) to 7.6 (SD 3.0) g/4 d, P<0.05), which remained unchanged with cream of tartar (5.6 (SD 3.0) g/4 d). Both sun-dried raisins and cream of tartar appear to be good stool softeners and to shorten intestinal transit time, although the fibre in sun-dried raisins has the added benefit of increasing faecal weight. Both sun-dried raisins and cream of tartar modulate the composition of faecal bile acids and SCFA in a way that has potential health benefits.

Calcium affects biomarkers of colon carcinogenesis after right hemicolectomy

BACKGROUND

In Western societies colonic cancer most frequently develops in the distal colon, largely as a result of the composition of the diet. Modulation of dietary factors is therefore an attractive modality to reduce colorectal cancer risk. This study aims to evaluate the potentially protective effects of calcium in right hemicolectomy patients.

MATERIALS AND METHODS

A randomized controlled cross-over intervention trial was performed with 1000 mg of elemental calcium per day for 2 months in 15 right hemicolectomy patients. Primary endpoints were proliferative activity, determined by immunohistochemical detection of BrdU-labeled cells (LI) in rectal biopsies, and cytotoxicity and alkaline phosphatase activity of faecal water. Secondary endpoints were bile acid composition in faeces.

RESULTS

Calcium-reduced LI in the superficial one-third of the crypt (from 0.84 +/- 0.27% to 0.37 +/- 0.08%, P = 0.04) and a trend towards a lower total LI and LI in the mid one-third of the crypt was observed. Alkaline phosphatase activity was reduced from 6.2 +/- 2.6 U mL-1 in the placebo period to 4.6 +/- 2.2 in the calcium period (P = 0.02), and a trend toward a lower cytotoxicity of faecal water was observed. No effect on total bile acids in faeces was observed, but calcium increased the percentage of deoxycholic acid (from 49.6 +/- 7.0% to 56.5 +/- 6.2%, P = 0.03) and decreased the percentages of cholic acid (from 10.3 +/- 4.7% to 5.8 +/- 2.7%, P = 0.05) and lithocholic acid (from 26.7 +/- 3.4% to 23.9 +/- 2.9%, P = 0.04).

CONCLUSION

Calcium may have a protective effect against colorectal cancer risk in right hemicolectomy patients.

Intestinal absorption and biliary secretion of ursodeoxycholic acid and its taurine conjugate

BACKGROUND

Ursodeoxycholic acid (UDCA) and its taurine conjugate (TUDCA) exert a protective effect in cholestatic liver diseases. A greater hepatoprotective effect of TUDCA has been suggested. Absorption appears to be a limiting factor and up to now has not been studied in man.

METHODS

We studied absorption and biliary bile acid secretion and composition after administration of UDCA and TUDCA in patients who had complete extrahepatic biliary obstruction caused by pancreatic carcinoma but had no intestinal or liver disease. After 5 days of intact enterohepatic circulation eight patients with a percutaneous biliary-duodenal drainage received, during two study periods, 1000 mg (1916.9 micromol; mean 29.6 micromol kg(-1)) TUDCA and 750 mg (1910.4 micromol; mean 29.5 micromol kg(-1)) UDCA in random order. Each patient served as his own control.

RESULTS

After UDCA and TUDCA administration the biliary UDCA content increased to 55.2% and 54.6% of total bile acids, respectively (not significant). Biliary secretion of cholic and chenodeoxycholic acids remained unchanged whereas that of lithocholic acid increased slightly. A total of 64.6% of the orally administered TUDCA and 55.1% of the UDCA was absorbed (not significant). After TUDCA administration, biliary UDCA was preferentially (95.4%) taurine-conjugated whereas after UDCA administration biliary UDCA was mainly (79.8%) glycine-conjugated.

CONCLUSIONS

After oral administration of TUDCA and UDCA, no significant differences in their absorption and in biliary bile acid secretion exist. Whether biliary enrichment with taurine conjugates of UDCA instead of glycine conjugates offers advantages in the treatment of cholestatic liver disease is unclear at present.

A prospective study of faecal bile acids and colorectal cancer

A prospective study of 7079 people aged 45-74 recruited through general practices in South Wales, Herefordshire and Edinburgh, Scotland was undertaken to test the hypothesis that faecal bile acids are implicated in the causation of large bowel cancer. The population was recruited between 1974 and 1980 and the response rate for stool collection was 67%. Bile acid analyses were performed on those cases that presented by 1990. It was decided in advance to examine the hypothesis separately for left- and right-sided bowel cancer because of known epidemiological differences between the two sites and to exclude the cases presenting within 2 years of the stool sample from the analyses because the cancer could have been present at recruitment and might have possibly affected faecal bile acid concentrations. Each case (n = 51 left-sided and 8 right-sided) was matched with three controls by age (within 5 years), sex, place of residence and time of providing the stool sample (within 3 months). Statistical analyses using conditional logistic regression showed no significant differences between the left-sided cases and controls for any of the concentrations of individual bile acids, total bile acid concentrations, faecal neutral steroids, percentage bacterial conversion and the ratio of lithocholic acid to deoxycholic acid concentrations. There was a statistically significant (P = 0.021) association of the presence of chenodeoxycholic acid (5/8 samples) in the right-sided cases compared with the controls (3/23), odds ratio 6.26 (95% confidence interval 1.19, 32.84). A high proportion of primary bile acids has also been found in other studies of patients with a genetic predisposition to proximal bowel cancer, however this pattern may also occur in low risk groups, such as Indian vegetarians, suggesting that they may predispose to right-sided bowel cancer only in the presence of other, as yet unknown factors. If bile acids are involved in the causation of large bowel cancer, they may be part of a complex set of interacting factors.

Biliary bile acids in primary biliary cirrhosis: effect of ursodeoxycholic acid

Bile acid composition in fasting duodenal bile was assessed at entry and at 2 years in patients with primary biliary cirrhosis (PBC) enrolled in a randomized, double-blind, placebo-controlled trial of ursodeoxycholic acid (UDCA) (10-12 mg/kg/d) taken as a single bedtime dose. Specimens were analyzed by a high-pressure liquid chromatography method that had been validated against gas chromatography. Percent composition in bile (mean +/- SD) for 98 patients at entry for cholic (CA), chenodeoxycholic (CDCA), deoxycholic (DCA), lithocholic (LCA), and ursodeoxycholic (UDCA) acids, respectively, were 57.4 +/- 18.6, 31.5 +/- 15.5, 8.0 +/- 9.3, 0.3 +/- 1.0, and 0.6 +/- 0.9. Values for CA were increased, whereas those for CDCA, DCA, LCA, and UDCA were decreased when compared with values in normal persons. Bile acid composition of the major bile acids did not change after 2 years on placebo medication. By contrast, in patients receiving UDCA for 2 years, bile became enriched with UDCA on average to 40.1%, and significant decreases were noted for CA (to 32.2%) and CDCA (to 19.5%). No change in percent composition was observed for DCA and LCA. Percent composition at entry and changes in composition after 2 years on UDCA were similar in patients with varying severity of PBC. In patients whose bile was not enriched in UDCA (entry and placebo-treated specimens), CA, CDCA, DCA, and the small amount of UDCA found in some of these specimens were conjugated to a greater extent with glycine (52%-64%) than with taurine (36%-48%). Treatment with UDCA caused the proportion of all endogenous bile acids conjugated with glycine to increase to 69% to 78%, while the proportion conjugated with taurine (22%-31%) fell (P <.05). Administered UDCA was also conjugated predominantly with glycine (87%).

Highly simplified method for gas-liquid chromatographic quantitation of bile acids and sterols in human stool

A simple method for the gas-liquid chromatographic quantitation of human fecal bile acids and sterols is described where bile acids are subjected to n-butyl ester derivatization, without prior isolation from the stool, followed by trimethylsilylation of the sterols and bile acids. Under these conditions, bile acid derivatives are well resolved from each other and from the trimethylsilyl ether derivatives of fecal sterols and no overlap occurs. The method was shown to be highly reproducible and recoveries were similar to those obtained with other methods used for fecal bile acid analysis. Application of the method for bile acid and sterol analysis in human stool is described.

Differences in the metabolism and disposition of ursodeoxycholic acid and of its taurine-conjugated species in patients with primary biliary cirrhosis

The clinical effectiveness of ursodeoxycholate in the treatment of liver disease may be limited by its poor absorption and extensive biotransformation. Because in vitro and in vivo studies suggest that the more hydrophilic bile acid tauroursodeoxycholate has greater beneficial effects than ursodeoxycholate, we have compared for the first time the absorption, metabolism, and clinical responses to these bile acids in patients with primary biliary cirrhosis (PBC). Twelve female patients with PBC were sequentially administered tauroursodeoxycholate and ursodeoxycholate (750 mg/d for 2 months) in a randomized, cross-over study. Bile acids were measured in serum, duodenal bile, urine, and feces by gas chromatography-mass spectrometry (GC-MS). Biliary ursodeoxycholate enrichment was higher during tauroursodeoxycholate administration (32.6% vs. 29.2% during ursodeoxycholate; P <.05). Lithocholic acid concentration was consistently higher in all biological fluids during ursodeoxycholate administration. Fecal bile acid excretion was the major route of elimination of both bile acids; ursodeoxycholate accounted for 8% and 23% of the total fecal bile acids during tauroursodeoxycholate and ursodeoxycholate administration, respectively (P <.05). Tauroursodeoxycholate was better absorbed than ursodeoxycholate, and, although it was partially deconjugated and reconjugated with glycine, it underwent reduced biotransformation to more hydrophobic metabolites. This comparative study suggests that tauroursodeoxycholate has significant advantages over ursodeoxycholate that may be of benefit for long-term therapy in PBC.

Faecal pH, bile acid and sterol concentrations in premenopausal Indian and white vegetarians compared with white omnivores

Faecal bulk, pH, water content, the concentrations of neutral sterols and bile acids and dietary intakes were measured in twenty-two Indian vegetarian, twenty-two white omnivorous and eighteen white vegetarian premenopausal women. Faecal bulk and water content were greater and pH lower in the Indian vegetarians. Total faecal animal sterol and coprostanol concentrations expressed on a dry-weight basis were lower in the vegetarians compared with the omnivores. The faecal sterol concentrations were correlated with dietary cholesterol intake. Primary bile acids were detected in six Indian vegetarians, two white vegetarians and two white omnivores; secondary bile acids were detected in all the white omnivores and vegetarian subjects but not in two of the Indian vegetarians. Total faecal free bile acid and conjugated bile acid concentrations were lower in the white vegetarians compared with the omnivores. Faecal lithocholic acid concentrations were lower in both Indian and white vegetarians. The lithocholic: deoxycholic acid ratio and coprostanol: total animal sterols ratio were significantly lower in the Indian vegetarians compared with the omnivores. Both ratios were positively correlated with faecal pH. Stepwise multiple regression analyses were undertaken in order to identify which nutrients influenced faecal pH, lithocholic and deoxycholic acid concentrations. The intakes of starch and dietary fibre were negatively associated with faecal concentrations of lithocholic and deoxycholic acid. Starch intake alone was negatively associated with faecal pH. The results of this study confirm that diets high in dietary fibre decrease faecal bile acid concentrations and suggest that the complex carbohydrates present in Indian vegetarian diets influence faecal pH and inhibit the degradation of faecal steroids.

Extrahepatic deposition and cytotoxicity of lithocholic acid: studies in two hamster models of hepatic failure and in cultured human fibroblasts

Effects of bile acids on tissues outside of the enterohepatic circulation may be of major pathophysiological significance under conditions of elevated serum bile acid concentrations, such as in hepatobiliary disease. Two hamster models of hepatic failure, namely functional hepatectomy (HepX), and 2-day bile duct ligation (BDL), as well as cultured human fibroblasts, were used to study the comparative tissue uptake, distribution, and cytotoxicity of lithocholic acid (LCA) in relation to various experimental conditions, such as binding of LCA to low-density lipoprotein (LDL) or albumin as protein carriers. Fifteen minutes after i.v. infusion of [24-(14)C]LCA, the majority of LCA in sham-operated control animals was recovered in liver, bile, and small intestine. After hepatectomy, a significant increase in LCA was found in blood, muscle, heart, brain, adrenals, and thymus. In bile duct-ligated animals, significantly more LCA was associated with blood and skin, and a greater than twofold increase in LCA was observed in the colon. In the hepatectomized model, the administration of LCA bound to LDL resulted in a significantly higher uptake in the kidneys and skin. The comparative time- and concentration-dependent uptake of [14C]LCA, [14C]chenodeoxycholic acid (CDCA), and [14C]cholic acid (CA) in cultured human fibroblasts was nonsaturable and remained a function of concentration. Initial rates of uptake were significantly increased by approximately tenfold, with decreasing hydroxylation of the respective bile acid. After 1 hour of exposure of fibroblasts to LCA, there was a significant, dose-dependent decrease in mitochondrial dehydrogenase activity from 18% to 34% of the control, at LCA concentrations ranging from 1 to 20 micromol/L. At a respective concentration of 100 and 700 micromol/L, CDCA caused a 35% and 99% inhibition of mitochondrial dehydrogenase activity. None of the bile acids tested, with the exception of 700 micromol/L CDCA, caused a significant release of cytosolic lactate dehydrogenase into the medium. In conclusion, we show that bile acids selectively accumulate in nonhepatic tissues under two conditions of impaired liver function. Furthermore, the extrahepatic tissue distribution of bile acids during cholestasis may be affected by serum lipoprotein composition. At a respective concentration of 1 and 100 micromol/L, LCA and CDCA induced mitochondrial damage in human fibroblasts, after just 1 hour of exposure. Therefore, enhanced extrahepatic uptake of hydrophobic bile acids during liver dysfunction, or disorders of lipoprotein metabolism, may have important implications for bile-acid induced cytotoxic effects in tissues of the systemic circulation.

Enhanced biliary excretion of lithocholate-3-sulfate by ursodeoxycholate-3,7-disulfate infusion in Eisai hyperbilirubinemic rat (EHBR)

Biliary excretion of lithocholate-3-sulfate and ursodeoxycholate 3,7-disulfate is markedly impaired in EHBR. In the present study, the effects of ursodeoxycholate 3,7-disulfate infusion on lithocholate-3-sulfate excretion were studied in EHBR and Sprague-Dawley rats. Although in control rats, ursodeoxycholate 3,7-disulfate infusion had no effect on biliary lithocholate-3-sulfate excretion, in EHBR it enhanced biliary lithocholate-3-sulfate excretion. Although ursodeoxycholate 3,7-disulfate dose-dependently inhibited lithocholate-3-sulfate binding by rat serum albumin and rat liver cytosol, it did not affect the serum clearance of lithocholate-3-sulfate in EHBR in vivo. These findings indicate that in EHBR, in which the major ATP-dependent organic anion transporter is impaired, the excretory pathway for ursodeoxycholate 3,7-disulfate may interact to that for lithocholate-3-sulfate.

Bile acid concentrations in serum and duodenal aspirates of healthy preterm infants: effects of gestational and postnatal age

In 41 healthy human-milk-fed preterm infants the preprandial total bile acid (BA) concentrations in serum and duodenal juice were simultaneous measured during the first 60 days of life. The infants were subdivided into four groups according to their gestational age: 6 infants with a gestational age of 27 and 28 weeks, 7 infants with a gestational age of 29 and 30 weeks, 21 infants with a gestational age of 31 and 32 weeks and 7 infants with a gestational age of 33 and 34 weeks. The BA levels were enzymatically determined using 3-alpha-hydroxysteroid dehydrogenase. In the duodenal juice, cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid and lithocholic acid were separately quantified by thin-layer chromatography. During the first month of life, the serum BA concentrations increased significantly with postnatal age (p < 0.01) but remained nearly constant during the second month of life. In the duodenal aspirates, the BA concentrations increased continuously up to the end of the observations period (p < 0.001). In the duodenal aspirates, the CA/CDCA ratio was high immediately after birth and decreased significantly with increasing postnatal age (p < 0.001). During the first weeks of life, the BA levels were preferentially conjugated with taurine, but in spite of the taurine-rich diet during the whole observation period the taurine/glycine ratio decreased with postnatal age (p < 0.001). In all samples of duodenal juice, the sum of primary BA was > 98% of total 3-alpha-hydroxy-BA. These data indicate that the establishment of an intestinal microbial flora necessary for intestinal BA transformation and the development of the enterohepatic BA circulation lasts some months of postnatal life. The serum BA concentration reflects hepatic synthesis, intestinal absorption, renal excretion and hepatocellular transport into bile in a very complex way which may limit the diagnostic value of serum BA during this time. Additionally, a duodenal BA concentration below 4 mmol/l, as found in this study during the first 2 weeks of life, may be of clinical importance due to its possible effects on fat absorption.

[Analysis of duodenal bile acids in patients with colorectal tumors and control subjects]

Bile acids are believed to play a role in the etiology of colorectal cancer. To investigate a possible relationship between bile acids and colorectal tumors, duodenal bile acids were analyzed in 18 patients with colorectal adenomas, 18 patients with colorectal carcinoma and 18 control subjects. Using high performance liquid chromatography and immobilized 3 alpha-hydroxysteroid dehydrogenase in column form, significant increases in the proportion of chenodeoxycholic acid and significant decreases in the proportion of deoxycholic acid and lithocholic acid were found in the bile of patients with colorectal adenoma or carcinoma compared with the control subjects. The data support the concept that bile acids have a role to play in the development of large bowel tumors.

[Modification of fecal bile acid excretion by fish oil in healthy probands]

Several studies indicated a protective effect of fish oil on colon carcinogenesis which might be due to alterations in prostaglandin E2 synthesis of the colonic mucosa. Additional effects on fecal bile acid excretion may also play a role since especially secondary bile acids are known to act as promoters in colon cancer development. In the present study possible influences on bile acid excretion were investigated in 12 healthy volunteers whose daily diet was supplemented for 4 weeks with 11 g of fish oil (FO) and corn oil (CO) per day, respectively. Fecal bile acids were analyzed by gas-liquid-chromatography. Fecal excretion of total bile acids was not different during the periods of FO and CO-supplementation (301.9 vs. 320.3 mg/day). However, a non-significant trend to a lower daily excretion of the secondary bile acid lithocholic acid was found after FO compared to CO-ingestion (99.6 vs. 109.4 mg/day; p = 0.22). Since secondary bile acids are known promoters of colon carcinogenesis, these findings may implicate a favorable situation with respect to colon cancer prevention.

Effect of colectomy with ileo-anal anastomosis on the biliary lipids

Total colectomy with ileo-anal anastomosis is an effective treatment for ulcerative colitis and familial adenomatous polyposis. The absence of the colon and the coexistence of bile acid malabsorption may increase bile lithogenicity, but data on biliary lipid composition in patients with this operation is lacking. Our aim was to assess bile lithogenicity, bile composition and mass of biliary lipids within the gallbladder. We studied 11 patients with total colectomy and ileo-anal anastomosis and 16 healthy controls. We measured the percentage composition of conjugated bile acids and the masses within the gallbladder of the three main biliary lipids. This method, in contrast with measurement of cholesterol saturation index, can determine the cause of bile lithogenicity in terms of absolute modifications of the biliary lipids. There was no difference in the cholesterol saturation index between patients and controls. Colectomy patients had reduced masses of all three biliary lipids (medians and ranges, mmol): cholesterol 0.11 (0.03-0.24) vs. 0.36 (0.02-0.96), P < 0.02; bile acid 1.62 (0.75-5.21) vs. 3.95 (1.27-8.70), P < 0.01; phospholipids 0.35 (0.07-0.69) vs. 1.14 (0.14-3.00), P < 0.002. They also had reduced per cent deoxycholic acid: 3.8 (0.0-27.6) vs. 17.4 (6.4-44.7), P < 0.005, and increased percent cholic acid: 44.9 (23.3-71.4) vs. 34.3 (19.2-57.9), P < 0.05. We conclude that, despite having bile acid malabsorption, patients with colectomy and ileo-anal anastomosis have a normal cholesterol saturation index, caused by a concomitant reduction in the masses of all three biliary lipids. The reduced per cent biliary deoxycholic acid may help explain the reduced cholesterol and phospholipid masses in these patients. Total colectomy with ileo-anal anastomosis does not seem to predispose to the formation of cholesterol gallstones.

Effects of oat and rye fractions on biliary and faecal bile acid profiles in Syrian golden hamsters (Mesocricetus auratus)

The effects of bran and starchy endosperm fractions of oat and rye on faecal weight and on biliary and faecal bile acids were studied in Syrian golden hamsters (Mesocricetus auratus). The animals fed on diets supplemented with steam-flaked oat bran, oat bran or rye bran had higher wet and dry weights of faeces compared with the animals fed on the fibre-free or low-fibre endosperm diets. A higher mean percentage of biliary cholic acid and a lower mean percentage of chenodeoxycholic and lithocholic (LCA) acids was observed in the bran-supplemented dietary groups. Animals fed on the bran-supplemented diets had increased daily faecal excretion of both total saponifiable and total free bile acids compared with the animals fed on fibre-free or endosperm-supplemented diets. The mean percentage of total saponifiable bile acids in the faeces was higher, and that of free bile acids lower in the animals fed on bran-supplemented diets. A significantly lower concentration of faecal free LCA was observed in the animals fed on the rye-bran diet. Both bran and endosperm diets reduced the faecal LCA:deoxycholic acid compared with the fibre-free diet, but the bran diets had a more pronounced effect than endosperm diets.

Biliary bile acids in cholelithiasis and carcinoma of the gall bladder

The role of biliary deoxycholate as an endogenous carcinogen and the possible association between cholelithiasis and the subsequent development of carcinoma of the gall bladder is unclear. This paper describes biliary bile acid analysis performed on three groups of patients, 10 with cholelithiasis, 10 with carcinoma of the gall bladder and 10 control patients. This is the first report of bile acid changes in carcinoma of the gall bladder. In these 30 patients the total bile acids concentration was highly variable (11.44-53.68 mg/ml). The mean ratio of primary to secondary bile acids was 3.5:1. This ratio was, however, significantly higher in cholelithiasis than in the control group (5.34:1; P < 0.001); patients with carcinoma of the gall bladder had significantly higher secondary bile acids (1:1; P < 0.001). This is due to a marked increase in the secondary bile acids and indicates that raised biliary deoxycholate concentrations are present in patients with carcinoma of the gall bladder and therefore may well be a factor in carcinogenesis.

Fecal bile acid excretion and composition in response to changes in dietary wheat bran, fat and calcium in the rat

The effect and possible interactive influence of different dietary amounts of wheat bran, fat and calcium on the fecal excretion, concentration and composition of bile acids was studied in Fischer-344 rats. The fecal bile acids were analyzed using gas-liquid chromatography. Dietary wheat bran increased both total bile acid excretion and fecal weight without changes in fecal bile acid concentration. The proportion of fecal hyodeoxycholic acid decreased with increasing dietary fiber, whereas that of lithocholic and deoxycholic acids increased significantly with fiber intake. The percent content of fecal chenodeoxycholic acid did not change. Increasing dietary fat led to an increase in bile acid excretion without changes in either fecal weight or bile acid concentration. In contrast, the level of dietary calcium did not affect the total excretion of bile acids. However, since calcium increased the fecal weight, it consequently diluted bile acids and decreased their fecal concentration. Dietary fat and calcium had no influence on fecal bile acid composition. There were no interactive effects of wheat bran, fat and calcium on fecal bile acids. The finding in this study that dietary fiber, fat and calcium induce significant changes in fecal bile acids may be of relevance to the potential of bile acids to promote carcinogenesis.

Faecal unconjugated bile acids in patients with colorectal cancer or polyps

The unconjugated faecal bile acid profiles of 14 patients with colorectal cancer, nine patients with polyps and 10 controls were compared using gas liquid chromatography, controlling for such confounding variables as cholecystectomy, gall stones and hepatic function. Patients with adenomatous polyps had a higher concentration of faecal bile acids (5.23 mumol/g, 2.16-13.67 (median, range) v 1.96, 0.91-6.97; p = 0.016) lithocholic acid (2.41, 0.88-3.22 v 1.07, 0.38-2.03; p = 0.013) and total secondary bile acids (5.23, 2.16-13.4 v 1.96, 0.73-6.63; p = 0.02) compared with control subjects. Patients with colorectal cancer had an increased (p = 0.029) proportion of secondary faecal bile acids (mol%) compared with controls (100, 96.5-100 v 95.19, 81.73-100) and the ratios of the primary bile acids, cholic and chenodeoxycholic acid, to their respective derivatives (secondary bile acids) were significantly lower in cancer patients compared with control and patients with polyps (p = 0.034 to 0.004). This study lends further support to the theory that bile acids may play a role in the development of polyps and colorectal cancer.

Determination of free and amidated bile acids by high-performance liquid chromatography with evaporative light-scattering mass detection

A simple reverse phase high-performance liquid chromatographic method for a simultaneous analysis of free, glycine- and taurine-amidated bile acids is described. The resolution of ursodeoxycholic, cholic, chenodeocycholic, deoxycholic, and lithocholic acids, either free or amidated with glycine and taurine, is achieved using a C-18 octadecylsilane column (30 cm length, 4 micron particle size) with a gradient elution of aqueous methanol (65----75%) containing 15 mM ammonium acetate, pH 5.40, at 37 degrees C. The separated bile acids are detected with a new evaporative light-scattering mass detector and by absorbance at 200 nm. A complete resolution of the 16 bile acids, including the internal standard nor-deoxycholic acid, is obtained within 55 min. Using the light-scattering mass detector, amidated bile acids and, for the first time, free bile acids can be detected with similar detection limits in the order of 2-7 nmol. The new detector improves the baseline and the signal-to-noise ratio over the UV detection as it is not affected by impurities present in the samples with higher molar absorptivity than bile acids or by the change in the mobile phase composition during the gradient. The method fulfills all the standard requirements of precision and accuracy and the linearity of the mass detector is over 5 decade the detection limit. The new method has been used for the direct analysis of bile acid in stools and bile with only a preliminary clean-up procedure using a C-18 reverse phase extraction.

Dietary effects of barley fibre, wheat bran and rye bran on bile composition and gallstone formation in hamsters

The effects of brewer's spent grain (BSG), wheat bran and rye bran on bile composition, gallstone formation and serum cholesterol were studied in Syrian golden hamsters. The frequency of gallstone formation in the animals fed diets supplemented with low (10%) and high (20%) concentrations of BSG or wheat bran was significantly lower than that of the animals fed a stone-provoking, fibre-free diet. The ratios of secondary to primary bile acids were lower in the animals fed the diets supplemented with a high dose of BSG, wheat bran and rye bran than in the controls. The ratio of LCA to DCA was reduced only in the animals fed the diet supplemented with rye bran as compared with controls. No significant changes in bile and serum cholesterol levels were observed in the experiment.

Faecal steroids and colorectal cancer: steroid profiles in subjects with adenomatous polyps of the large bowel

In this necroscopy study the relation between carriage and size of colorectal polyps was correlated with luminal steroid concentrations in respect to malignant risk. Of the 92 subjects entered into the study, 68 had adenomatous polyps of the large bowel, of which 19 had adenomas > 0.9 cm in diameter (large adenomas), 26 in the range 0.5-0.9 cm in diameter (medium adenomas) and 23 of 0.4 cm or less in diameter (small adenomas). Sixty-three percent of subjects carrying large adenomas and 26% of persons carrying small adenomas had an abnormal ratio (> 1.0) of lithocholic acid to deoxycholic acid in intestinal contents as compared to 17% of the adenoma-free comparison group (n = 24). These findings support the suggestion that the ratio of lithocholic acid to deoxycholic acid as a faecal marker may be a useful adjunct to screening procedures for colorectal cancer.

The use of negative ion thermospray liquid chromatography/tandem mass spectrometry for the determination of bile acids and their glycine conjugates

A study was carried out on the negative ion thermospray liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry of a group of bile acids and their glycine conjugates. The liquid chromatographic/tandem mass spectrometric experiments were performed using low-energy collisions on a triple-quadrupole mass spectrometer. It was found that relatively high collision energies and collision gas pressures were required to produce fragmentation and that some unusual fragments were produced.

Unchanged levels of keto bile acids in bile after cholecystectomy

Cholecystectomy has been hypothesized to cause increased levels of potentially harmful secondary bile acids due to prolonged exposure of primary bile acids to intestinal bacteria. In the present study, we analyzed duodenal bile of the same patients before and after cholecystectomy for keto bile acids and hydroxy bile acids. The ratios of individual keto bile acids to their corresponding precursor hydroxy bile acids were not significantly different before and after cholecystectomy. Keto bile acids constituted 2.5 +/- 1.3 and 2.2 +/- 0.9 mol% of hydroxy bile acids in duodenal bile. 3 alpha-Hydroxy-12-oxo-5 beta-cholanoic acid derived from deoxycholic acid was the main keto bile acid in bile contributing 80 mol% to total keto bile acids. There was a strong positive correlation between 3 alpha-hydroxy-12-oxo-5 beta-cholanoic acid and its precursor deoxycholic acid in bile (r = 0.88; p less than 0.0005). Our findings prove that 7 weeks after cholecystectomy the percentage of keto bile acids in bile as compared to hydroxy bile acids is not increased.

Bile acids in human breast cyst fluid: the identification of lithocholic acid

Breast cyst fluid (BCF) aspirated from 12 women with fibrocystic disease of the breast and sera obtained simultaneously were analyzed for bile acids. Analysis was performed by gas-liquid chromatography of the acetoxy methyl esters of the bile acids prepared after alkaline hydrolysis of the bile salts. An internal standard served to correct for methodological losses. Low levels of bile acids were found in serum samples, precluding overt hepatobiliary complications. Deoxycholic acid (17-160 mumol/L), chenodeoxycholic acid (18-305 mumol/L), and cholic acid (3-119 mumol/L) were detected in 11 of 12 samples of BCF. In 2 cases, chosen at random, the identities of the bile acids were verified by mass spectrometry. Lithocholic acid (9-23 mumol/L), a reported cocarcinogen, was detected in 6 of the 12 samples of BCF. This is the first report of the presence of lithocholic acid in BCF with confirmation by Mass spectrometry. There was no correlation between the levels of individual bile acids and those of potassium ion, Na+/K+, estriol-3-sulfate, or 16 alpha-hydroxyandrogen sulfates that had been quantified previously in these samples. There was borderline correlation between concentrations of total bile acids and K+ (P less than 0.06) and Na+/K+ (P less than 0.07). Yet to be elucidated are the mechanism of accumulation of bile acids in BCF and whether levels of particular bile acids in BCF may serve to identify that small subset of women with fibrocystic disease at risk for developing breast cancer.

Lithocholate in liver tissue with obstructive jaundice

The existence of tissue-bound lithocholate in liver tissue was first suggested by Nair et al. (Lipids 1988;12:922-929). Since lithocholate is well known to be cholestatic, we investigated whether tissue-bound lithocholate, if present, can be correlated to liver dysfunction in obstructive jaundice. Tissue-bound lithocholate in liver tissues of 7 patients with obstructive jaundice was analyzed using gas chromatography-mass spectrometry-selected ion monitoring. We found no accumulation of lithocholate, including tissue-bound form, indicating that the role of lithocholate in inducing hepatic dysfunction in obstructive jaundice is minimal, if any.

Bile acids, neutral steroids, and bacteria in feces as affected by a mixed, a lacto-ovovegetarian, and a vegan diet

In a metabolic ward 12 healthy male subjects consumed mixed Western (M), lacto-ovovegetarian (L), and vegan (V) diets in a randomized order for 20 d each. The concentrations of deoxycholic acid, isolithocholic acid, and total bile acids in 4-d composites of feces on the L and V diets were significantly lower than on the M diet. The chenodeoxycholic-to-isolithocholic plus lithocholic acid ratio was significantly higher on the V diet. The concentrations of coprostanol and of coprostanol plus cholesterol were highest on M diet and lowest on V diet. The number of fecal lactobacilli and enterococci on the V diet was significantly lower than on the M or the L diets. This study showed a decrease in the concentration of fecal (secondary) bile acids by the L and the V diets and an alteration of the fecal flora composition by the V diet.

High pressure liquid chromatographic analysis of conjugated bile acids in human bile: simultaneous resolution of sulfated and unsulfated lithocholyl amidates and the common conjugated bile acids

A reversed phase high pressure liquid chromatography (HPLC) system capable of simultaneously separating four lithocholyl species (sulfated and unsulfated forms of lithocholylglycine and lithocholyltaurine) as well as the eight other major conjugated bile acids present in human bile is described. The system uses a C18 octadecylsilane column and isocratic elution with methanol phosphate buffer, pH 5.35. Relative bile acid concentration is determined by absorbance at 200 nm. Retention times relative to chenodeoxycholylglycine are reported for the four lithocholic acid forms, the glycine and taurine amidate of the four major bile acids present in human bile (cholic, chenodeoxycholic, ursodeoxycholic, and deoxycholic), and for their corresponding unconjugated forms. Retention times are also reported for the glycine and taurine amidates as well as the unconjugated form of the C23 norderivatives of these bile acids. Maximal absorbance of bile acid amidates is at 200 nm and is very similar for the (unsulfated) glycine and taurine amidates. Sulfated lithocholyl amidates exhibit molar absorptivities at 200 nm which are 1.4 times greater than that of non-sulfated lithocholyl amidates. Unconjugated bile acid absorbance at 200 nm or 210 nm is 20 to 30 times less than that of corresponding peptide conjugates. The method has been applied to samples of gallbladder bile obtained from 14 healthy subjects to define the pattern of conjugated bile acids present in human bile.

Fecal steroids and colorectal cancer

The fecal steroid profiles of healthy subjects were compared with those of colorectal cancer (CRC) patients. The multicomponent profiles did not differ qualitatively in that CRC patients, like control subjects, had similar fecal steroids. The major bile acids detected in fecal extracts were lithocholic acid (LCA) and deoxycholic acid (DCA). The major sterol of animal origin was cholesterol and its bacterial metabolite coprostanol, whereas the major plant sterols were beta-sitosterol, stigmasterol, campesterol, and their corresponding bacterial metabolites. CRC patients excreted higher amounts of total major bile acids (LCA and DCA) than did the control group, but this difference was not significant. However, the LCA-to-DCA ratio was much higher in the CRC group [(1.43, p less than 0.01) compared with the control group (0.72)]. The control group excreted significantly higher amounts of total neutral sterols (p less than 0.001), sterols of animal origin (p less than 0.001), and plant sterols (p less than 0.001) compared with the CRC group; the plant sterols represented a much lower proportion of excreted total neutral sterols in the CRC group (p greater than 0.001) compared with the control group. We propose the following hypotheses. The LCA-to-DCA ratio may be an important discriminant market for CRC susceptibility. The fecal LCA-to-DCA ratio may depend on the differential hepatic synthesis of their respective precursors chenodeoxycholic acid (CDCA) and cholic acid. Hepatic synthesis of CDCA may be increased by more efficient conservation of dietary cholesterol because it has been shown that cholesterol of exogenous origin is the main precursor of this bile acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in bile salt composition after cholecystectomy and ileal resection

The effect of ileal resection and cholecystectomy on bile salt metabolism was studied in female prairie dogs 4 weeks after either a sham laparotomy, cholecystectomy, ileal resection, or cholecystectomy and ileal resection. Bile was collected from a common bile duct cannula at hourly intervals for 12 hours. Pool sizes and synthetic rates of primary and secondary bile salts were determined from washout curves. Cholate, chenodeoxycholate, deoxycholate, and lithocholate levels were determined by gas chromatography from pooled collections of bile. After cholecystectomy and ileal resection, the pool sizes of primary and secondary bile salts were significantly reduced to amounts that were much less than the pool sizes after either procedure alone. Primary bile salt synthesis was significantly increased after combined cholecystectomy and ileal resection, to the same degree as cholecystectomy alone. After the combined procedures, there was a decrease in the proportion of cholate in hepatic bile associated with an increase in chenodeoxycholate, deoxycholate, and lithocholate levels. The data suggest that after the loss of both ileum and gallbladder the bile salt pool sizes are drastically reduced, the synthesis of primary bile salts is increased, and the proportion of secondary bile salts is increased. Cholecystectomy should be avoided, if possible, in patients with ileal resection in order to conserve the bile salt pool and prevent severe fat malabsorption.

Nuclear magnetic resonance spectroscopy of bile acids. Development of two-dimensional NMR methods for the elucidation of proton resonance assignments for five common hydroxylated bile acids, and their parent bile acid, 5 beta-cholanoic acid

The complete 1H nuclear magnetic resonance assignments have been made for the common mono-, di-, and trihydroxy 5 beta-cholanoic acids; lithocholic acid, chenodeoxycholic acid, ursodeoxycholic acid, deoxycholic acid, cholic acid, and the unsubstituted parent compound, 5 beta-cholanoic acid, by heteronuclear-correlated two-dimensional NMR. The known 13C chemical shifts of these compounds were used to make the proton resonance assignments, and consistency of the carbon and proton assignments was verified by expected changes due to substituent effects. This has led to clarification of previously published 13C NMR resonance assignments. Addition of the 3 alpha, 7 alpha, and 12 alpha hydroxyl substituent effects derived from the mono- and dihydroxycholanoic acids yielded predicted values for proton chemical shifts of the trihydroxy-substituted 5 beta-cholanoic acid, cholic acid, that agreed well with experimental values. It is suggested that the individual substituent effects can be used to predict proton chemical shifts for hydroxycholanic acids containing other combinations of 3 alpha, 7 alpha, 7 beta, and 12 alpha hydroxyl groups.

Fecal bile acid excretion pattern in colonic cancer patients

Epidemiological investigations have shown an association between the incidence of colonic cancer, dietary habits, and bile acid metabolism. We analyzed the fecal bile acid excretion pattern in 23 patients with colonic carcinoma and in 21 controls. We determined the total bile acid concentration, the concentration of individual bile acids as a measure for bacterial degradation, and the degree of sulfation. Separation of nonsulfated and sulfated bile acids was achieved by the lipophilic anion-exchanger DEAP-Sephadex-LH 20, quantification of individual bile acids by gas-liquid chromatography. Corresponding with a significantly lower stool mass per day, colonic cancer patients had a lower daily bile acid excretion. But we found no statistically significant difference between the groups in the fecal concentration of total or individual bile acids or their mode of conjugation. There was a wide variation of total bile acid concentration within each group. Most bile acids were expectedly in the free state, only a low percentage in the glycine- or taurine-conjugated form. The sulfated fraction was small and not different in the two groups. Although our data do not refute the hypothesis of bile acids being implicated in the pathogenesis of colorectal cancer, they do not support it.

Metabolism of lithocholic and chenodeoxycholic acids in the squirrel monkey

Metabolism of lithocholic acid (LCA) and chenodeoxycholic acid (CDCA) was studied in the squirrel monkey to clarify the mechanism of the lack of toxicity of CDCA in this animal. Radioactive LCA was administered to squirrel monkeys with biliary fistula. Most radioactivity was excreted in the bile in the form of unsulfated lithocholyltaurine. The squirrel monkey thus differs from humans and chimpanzees, which efficiently sulfate LCA, and is similar to the rhesus monkey and baboon in that LCA is poorly sulfated. When labeled CDCA was orally administered to squirrel monkeys, less than 20% of the dosed radioactivity was recovered as LCA and its further metabolites in feces over 3 days, indicating that bacterial metabolism of CDCA into LCA is strikingly less than in other animals and in humans. It therefore appears that LCA, known as a hepatotoxic secondary bile acid, is not accumulated in the squirrel monkey, not because of its rapid turnover through sulfation, but because of the low order of its production.

Ileal and colonic mucosal bile acids in Crohn's disease and right colonic carcinoma

Bile acids are supposed to promote colonic cancer. In Crohn's disease, colonic carcinomas are relatively rare. We, therefore, compared ileal and right colonic mucosal bile acids analysed by gas-liquid chromatography in 8 patients with ileal Crohn's disease (14-48 yrs.) and 7 patients with right colonic carcinoma (28-77 yrs.) who underwent surgery. In both ileal and colonic mucosa, nonsulphated bile acid concentrations were somewhat higher in Crohn's disease (20.98 micrograms/g +/- 4.77 SEM; 12.09 micrograms/g +/- 2.55) than in colonic carcinoma (16.06 micrograms/g +/- 3.46; 7.75 micrograms/g +/- 4.28). In ileal mucosa, percentages of lithocholic and deoxycholic acids were slightly higher in colonic carcinoma (3.9%; 23.2%) than in Crohn's disease (1.1%; 14.9%). In colonic mucosa, carcinoma patients had more lithocholic (7.6%) and less deoxycholic acid (11.9%) than patients with Crohn's disease (1.7%; 20.3%). Bile acid sulphate esters were similar in both diseases (ca. 3.0 micrograms/g in ileal, 1.4 micrograms/g in colonic mucosa). Our results show that ileal and right colonic mucosal nonsulphated bile acids tend to be even lower in right colonic carcinoma than in Crohn's disease. This agrees well with our earlier findings of low mucosal bile acid concentrations in patients with left colonic carcinoma (Tokai J Exp Clin Med 8: 59-69, 1983) and does not support the assumption that bile acids are envolved in right colonic carcinogenesis.

Critical evaluation of the existence of so-called tissue-bound lithocholate in human liver tissue by selected ion monitoring

Monohydroxy bile acids in liver tissue may be of importance because of their hepatotoxicity and strong cholestatic effects. Recently, the existence of lithocholate in liver tissue in two forms was suggested by Nair et al. (Lipids. 1977. 12: 922-929) i.e., either in free form or as so-called tissue-bound lithocholate released exclusively by cholylglycine hydrolase treatment. The presence of the latter aroused much interest in relation to its hepatotoxicity and possible role in tumor induction. In the present investigation lithocholyl-epsilon-L-lysine, proposed as the predominant tissue-bound bile acid, was synthesized and its metabolic behavior was tested. Lithocholyl-epsilon-lysine was not deconjugated by cholylglycine hydrolase treatment but only by alkaline hydrolysis. Bile acids in seven cirrhotic and three noncirrhotic liver samples were extracted with 95% ethanol-0.1% ammonium hydroxide. The bile acids in the extract and residue were quantified by glass capillary gas-liquid chromatography using selected ion monitoring. The presence of so-called tissue-bound lithocholate could not be substantiated in either cirrhotic or noncirrhotic liver tissues. Nearly complete extraction of lithocholate was achieved by the use of organic solvent alone. Therefore, tissue-bound lithocholate, if it exists at all, may be attached to tissue by a physical linkage which can be disrupted by the use of conventional organic solvent.

Correlation of bile acid composition between liver tissue and bile

Bile acid composition of ten paired human livers and bile specimens were compared with gas chromatography-selected ion monitoring. The bile acid composition in liver and in bile was found to be similar but not identical. This difference seems to be a reflection of bile acid synthesis in liver tissue. It is suggested that analysis of bile acid composition in liver tissue is useful to evaluate abnormality of bile acid synthesis in several pathological states.

Fecal bile acids and neutral sterols in Japanese with large bowel carcinoma

We compared the level of fecal bile acids and neutral sterols in 15 Japanese with large bowel carcinoma and 10 healthy controls. There was no significant difference in the amount of total fecal bile acids and neutral sterols between the patients and the controls. However, the amount of primary bile acids, especially chenodeoxycholic acid, tended to be higher in the patients. Conversely, lithocholic, beta-lithocholic and 3 alpha-hydroxy-12-ketocholanoic acid levels were higher in the controls. Trace amounts of 3 alpha-hydroxy-6-ketocholanoic acid were detected in some of the patients; none was found in the controls. Although a hasty conclusion should be avoided in the present study, it is of considerable interest that there was a difference in fecal bile acid composition between large bowel carcinoma patients and healthy controls.

Effect of 7-ketolithocholic acid on bile acid metabolism in humans

The effect of 7-ketolithocholic acid on biliary bile acid composition, cholesterol saturation, and as an intermediate in the conversion of chenodeoxycholic acid to ursodeoxycholic acid was investigated in 5 subjects with gallstones. After 7-ketolithocholic acid (400 mg/day) was administered orally for 14 days, biliary bile acid composition changed: The proportion of cholic acid decreased (from 45% to 19%), deoxycholic acid decreased (from 15% to 10%), chenodeoxycholic acid increased markedly (from 36% to 59%), ursodeoxycholic acid increased (from 36% to 59%), ursodeoxycholic acid increased (from 2% to 7%), and lithocholic acid increased (from 2% to 5%), while only trace amounts of 7-ketolithocholic acid were detected. During this treatment, the biliary lithogenic index fell from 2.6 to 0.9 and was accompanied by a pronounced drop in biliary cholesterol concentration. After biliary bile acid levels became constant [24-14C]chenodeoxycholic acid was given intravenously as a pulse-label, and the resultant biliary ursodeoxycholic acid and lithocholic acid specific activity curves showed a precursor--product relationship with chenodeoxycholic acid. Similarly, when uniformly labeled 7-[24-14C]ketolithocholic acid was fed (400 mg/day, 1000 +/- 100 dpm/mg) the specific activities of biliary chenodeoxycholic acid and ursodeoxycholic acid became constant and approximated each other, but these were only 75% as high as the fed 7-ketolithocholic acid. These results indicate that 7-ketolithocholic acid is absorbed, and suppresses endogenous bile acid production and biliary cholesterol secretion. Both isotopic experiments infer that ursodeoxycholic acid and lithocholic acid are formed from chenodeoxycholic acid and not from 7-ketolithocholic acid. The reduction in biliary lithogenic index and in cholesterol concentration suggest that low doses of 7-ketolithocholic acid may be effective in dissolving gallstones.

Hepatic alterations during total parenteral nutrition in patients with inflammatory bowel disease: a possible consequence of lithocholate toxicity

In order to understand the mechanism of hepatic abnormalities appearing during total parenteral nutrition, biliary bile acid composition and liver function tests were examined serially in 15 patients undergoing total parenteral nutrition for inflammatory bowel disease. In all 12 patients who underwent duodenal intubation before initiation of total parenteral nutrition, lithocholic acid accounted for less than 1% of total biliary bile acids. After 11-22 days of total parenteral nutrition, lithocholic acid accounted for 7%-15% of biliary bile acids in 5 patients and less than 1% of biliary bile acids in 10 patients. In the 5 patients with elevated levels of biliary lithocholic acid, serum alkaline phosphatase and aminotransferase activities rose progressively at serial determinations, the increase being significant after 2 wk of total parenteral nutrition. These results suggest that lithocholic acid may be involved in the hepatic lesions observed in patients undergoing total parenteral nutrition.