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Sample records for human bile salt

  1. Evolutionary diversity of bile salts in reptiles and mammals, including analysis of ancient human and extinct giant ground sloth coprolites

    PubMed Central

    2010-01-01

    Background Bile salts are the major end-metabolites of cholesterol and are also important in lipid and protein digestion and in influencing the intestinal microflora. We greatly extend prior surveys of bile salt diversity in both reptiles and mammals, including analysis of 8,000 year old human coprolites and coprolites from the extinct Shasta ground sloth (Nothrotherium shastense). Results While there is significant variation of bile salts across species, bile salt profiles are generally stable within families and often within orders of reptiles and mammals, and do not directly correlate with differences in diet. The variation of bile salts generally accords with current molecular phylogenies of reptiles and mammals, including more recent groupings of squamate reptiles. For mammals, the most unusual finding was that the Paenungulates (elephants, manatees, and the rock hyrax) have a very different bile salt profile from the Rufous sengi and South American aardvark, two other mammals classified with Paenungulates in the cohort Afrotheria in molecular phylogenies. Analyses of the approximately 8,000 year old human coprolites yielded a bile salt profile very similar to that found in modern human feces. Analysis of the Shasta ground sloth coprolites (approximately 12,000 years old) showed the predominant presence of glycine-conjugated bile acids, similar to analyses of bile and feces of living sloths, in addition to a complex mixture of plant sterols and stanols expected from an herbivorous diet. Conclusions The bile salt synthetic pathway has become longer and more complex throughout vertebrate evolution, with some bile salt modifications only found within single groups such as marsupials. Analysis of the evolution of bile salt structures in different species provides a potentially rich model system for the evolution of a complex biochemical pathway in vertebrates. Our results also demonstrate the stability of bile salts in coprolites preserved in arid climates

  2. Crystal structure of the catalytic domain of human bile salt activated lipase.

    PubMed Central

    Terzyan, S.; Wang, C. S.; Downs, D.; Hunter, B.; Zhang, X. C.

    2000-01-01

    Bile-salt activated lipase (BAL) is a pancreatic enzyme that digests a variety of lipids in the small intestine. A distinct property of BAL is its dependency on bile salts in hydrolyzing substrates of long acyl chains or bulky alcoholic motifs. A crystal structure of the catalytic domain of human BAL (residues 1-538) with two surface mutations (N186D and A298D), which were introduced in attempting to facilitate crystallization, has been determined at 2.3 A resolution. The crystal form belongs to space group P2(1)2(1)2(1) with one monomer per asymmetric unit, and the protein shows an alpha/beta hydrolase fold. In the absence of bound bile salt molecules, the protein possesses a preformed catalytic triad and a functional oxyanion hole. Several surface loops around the active site are mobile, including two loops potentially involved in substrate binding (residues 115-125 and 270-285). PMID:11045623

  3. Bile salt recognition by human liver fatty acid binding protein.

    PubMed

    Favretto, Filippo; Santambrogio, Carlo; D'Onofrio, Mariapina; Molinari, Henriette; Grandori, Rita; Assfalg, Michael

    2015-04-01

    Fatty acid binding proteins (FABPs) act as intracellular carriers of lipid molecules, and play a role in global metabolism regulation. Liver FABP (L-FABP) is prominent among FABPs for its wide ligand repertoire, which includes long-chain fatty acids as well as bile acids (BAs). In this work, we performed a detailed molecular- and atomic-level analysis of the interactions established by human L-FABP with nine BAs to understand the binding specificity for this important class of cholesterol-derived metabolites. Protein-ligand complex formation was monitored using heteronuclear NMR, steady-state fluorescence spectroscopy, and mass spectrometry. BAs were found to interact with L-FABP with dissociation constants in the narrow range of 0.6-7 μm; however, the diverse substitution patterns of the sterol nucleus and the presence of side-chain conjugation resulted in complexes endowed with various degrees of conformational heterogeneity. Trihydroxylated BAs formed monomeric complexes in which single ligand molecules occupied similar internal binding sites, based on chemical-shift perturbation data. Analysis of NMR line shapes upon progressive addition of taurocholate indicated that the binding mechanism departed from a simple binary association equilibrium, and instead involved intermediates along the binding path. The co-linear chemical shift behavior observed for L-FABP complexes with cholate derivatives added insight into conformational dynamics in the presence of ligands. The observed spectroscopic features of L-FABP/BA complexes, discussed in relation to ligand chemistry, suggest possible molecular determinants of recognition, with implications regarding intracellular BA transport. Our findings suggest that human L-FABP is a poorly selective, universal BA binder. PMID:25639618

  4. Bile salt recognition by human liver fatty acid binding protein.

    PubMed

    Favretto, Filippo; Santambrogio, Carlo; D'Onofrio, Mariapina; Molinari, Henriette; Grandori, Rita; Assfalg, Michael

    2015-04-01

    Fatty acid binding proteins (FABPs) act as intracellular carriers of lipid molecules, and play a role in global metabolism regulation. Liver FABP (L-FABP) is prominent among FABPs for its wide ligand repertoire, which includes long-chain fatty acids as well as bile acids (BAs). In this work, we performed a detailed molecular- and atomic-level analysis of the interactions established by human L-FABP with nine BAs to understand the binding specificity for this important class of cholesterol-derived metabolites. Protein-ligand complex formation was monitored using heteronuclear NMR, steady-state fluorescence spectroscopy, and mass spectrometry. BAs were found to interact with L-FABP with dissociation constants in the narrow range of 0.6-7 μm; however, the diverse substitution patterns of the sterol nucleus and the presence of side-chain conjugation resulted in complexes endowed with various degrees of conformational heterogeneity. Trihydroxylated BAs formed monomeric complexes in which single ligand molecules occupied similar internal binding sites, based on chemical-shift perturbation data. Analysis of NMR line shapes upon progressive addition of taurocholate indicated that the binding mechanism departed from a simple binary association equilibrium, and instead involved intermediates along the binding path. The co-linear chemical shift behavior observed for L-FABP complexes with cholate derivatives added insight into conformational dynamics in the presence of ligands. The observed spectroscopic features of L-FABP/BA complexes, discussed in relation to ligand chemistry, suggest possible molecular determinants of recognition, with implications regarding intracellular BA transport. Our findings suggest that human L-FABP is a poorly selective, universal BA binder.

  5. Bile salt-stimulated lipase: an animal model for human lactation

    SciTech Connect

    Hamosh, M.; Freed, L.M.; York, C.M.; Sturman, J.A.; Hamosh, P.

    1986-03-01

    To date, bile salt-stimulated lipase (BSSL), an important digestive enzyme for the newborn, has only been described in the milk of primates - human and gorilla. The authors report the presence of BSSL in milks of dog and cat. Serial collections from two dogs (day 1-49) and cats (day 5-57) were analyzed for BSSL activity using a /sup 3/H-triolein emulsion as substrate. Comparable analyses of pooled, term human milk were made for comparison. BSSL activity in individual dog milks (x = 32.0; range: 4.8-107.4 U/ml) was similar, while that in cat milk (x = 6.6; range: 2.2-16.9 U/ml) was lower than in human milk (x = 37.0; range: 10-80 U/ml; n = 35). Longitudinal patterns for BSSL differed depending upon the enzyme source. Dog, cat and human milk BSSL all showed a neutral to alkaline pH optimum (pH 7.0-8.4), stability at low pH, and 95-100% inhibition (at concentrations of 0.6 mM) by NaCl and eserine. BSSL activity from all sources had an obligate requirement for primary bile salts. These data are the first to show BSSL activity in milk from mammals other than human and gorilla. Presence of BSSL in nonprimate milk will permit the careful study of BSSL biology in the mammary gland as well as its role in neonatal fat digestion.

  6. COMPLEX EVOLUTION OF BILE SALTS IN BIRDS.

    PubMed

    Hagey, Lee R; Vidal, Nicolas; Hofmann, Alan F; Krasowski, Matthew D

    2010-10-01

    Bile salts are the major end-metabolites of cholesterol and are important in lipid digestion and shaping of the gut microflora. There have been limited studies of bile-salt variation in birds. The purpose of our study was to determine bile-salt variation among birds and relate this variation to current avian phylogenies and hypotheses on the evolution of bile salt pathways. We determined the biliary bile-salt composition of 405 phylogenetically diverse bird species, including 7 paleognath species. Bile salt profiles were generally stable within bird families. Complex bile-salt profiles were more common in omnivores and herbivores than in carnivores. The structural variation of bile salts in birds is extensive and comparable to that seen in surveys of bile salts in reptiles and mammals. Birds produce many of the bile salts found throughout nonavian vertebrates and some previously uncharacterized bile salts. One difference between birds and other vertebrates is extensive hydroxylation of carbon-16 of bile salts in bird species. Comparison of our data set of bird bile salts with that of other vertebrates, especially reptiles, allowed us to infer evolutionary changes in the bile salt synthetic pathway.

  7. COMPLEX EVOLUTION OF BILE SALTS IN BIRDS

    PubMed Central

    Hagey, Lee R.; Vidal, Nicolas; Hofmann, Alan F.; Krasowski, Matthew D.

    2010-01-01

    Bile salts are the major end-metabolites of cholesterol and are important in lipid digestion and shaping of the gut microflora. There have been limited studies of bile-salt variation in birds. The purpose of our study was to determine bile-salt variation among birds and relate this variation to current avian phylogenies and hypotheses on the evolution of bile salt pathways. We determined the biliary bile-salt composition of 405 phylogenetically diverse bird species, including 7 paleognath species. Bile salt profiles were generally stable within bird families. Complex bile-salt profiles were more common in omnivores and herbivores than in carnivores. The structural variation of bile salts in birds is extensive and comparable to that seen in surveys of bile salts in reptiles and mammals. Birds produce many of the bile salts found throughout nonavian vertebrates and some previously uncharacterized bile salts. One difference between birds and other vertebrates is extensive hydroxylation of carbon-16 of bile salts in bird species. Comparison of our data set of bird bile salts with that of other vertebrates, especially reptiles, allowed us to infer evolutionary changes in the bile salt synthetic pathway. PMID:21113274

  8. Bile salt metabolism in tropical sprue.

    PubMed

    Bevan, G; Engert, R; Klipstein, F A; Maldonado, N; Rubulis, A; Turner, M D

    1974-04-01

    Mean and peak jejunal bile salt concentrations during digestion of a standard fat meal were found to be significantly lower in six Puerto Rican patients with untreated tropical sprue, all of whom had steatorrhoea, than in six asymptomatic subjects who had normal fat absorption. Bile salt pool size and turnover time did not differ significantly in the two groups.It is suggested that bile salt concentrations may be reduced in the proximal small intestine of patients with tropical sprue as a result of excessive dilution by intestinal fluid. The finding of low bile salt concentrations in two asymptomatic subjects indicates that bile salt lack alone may not be sufficient to produce steatorrhoea.

  9. Bile salts as semiochemicals in fish

    USGS Publications Warehouse

    Buchinger, Tyler J.; Li, Weiming; Johnson, Nicholas S.

    2014-01-01

    Bile salts are potent olfactory stimuli in fishes; however the biological functions driving such sensitivity remain poorly understood. We provide an integrative review of bile salts as semiochemicals in fish. First, we present characteristics of bile salt structure, metabolism, and function that are particularly relevant to chemical communication. Bile salts display a systematic pattern of structural variation across taxa, are efficiently synthesized, and are stable in the environment. Bile salts are released into the water via the intestine, urinary tract, or gills, and are highly water soluble. Second, we consider the potential role of bile salts as semiochemicals in the contexts of detecting nearby fish, foraging, assessing risk, migrating, and spawning. Lastly, we suggest future studies on bile salts as semiochemicals further characterize release into the environment, behavioral responses by receivers, and directly test the biological contexts underlying olfactory sensitivity.

  10. Functional genomic analysis of bile salt resistance in Enterococcus faecium

    PubMed Central

    2013-01-01

    Background Enterococcus faecium is a Gram-positive commensal bacterium of the mammalian intestinal tract. In the last two decades it has also emerged as a multi-resistant nosocomial pathogen. In order to survive in and colonize the human intestinal tract E. faecium must resist the deleterious actions of bile. The molecular mechanisms exploited by this bacterium to tolerate bile are as yet unexplored. Results In this study we used a high-throughput quantitative screening approach of transposon mutant library, termed Microarray-based Transposon Mapping (M-TraM), to identify the genetic determinants required for resistance to bile salts in E. faecium E1162. The gene gltK, which is predicted to encode a glutamate/aspartate transport system permease protein, was identified by M-TraM to be involved in bile resistance. The role of GltK in bile salt resistance was confirmed by the subsequent observation that the deletion of gltK significantly sensitized E. faecium E1162 to bile salts. To further characterize the response of E. faecium E1162 to bile salts, we performed a transcriptome analysis to identify genes that are regulated by exposure to 0.02% bile salts. Exposure to bile salts resulted in major transcriptional rearrangements, predominantly in genes involved in carbohydrate, nucleotide and coenzyme transport and metabolism. Conclusion These findings add to a better understanding of the molecular mechanisms by which E. faecium responds and resists the antimicrobial action of bile salts. PMID:23641968

  11. Bile salt-stimulated lipase of human milk: characterization of the enzyme from preterm and term milk

    SciTech Connect

    Freed, L.M.; Hamosh, P.; Hamosh, M.

    1986-03-01

    The bile salt-stimulated lipase (BSSL) of human milk is an important digestive enzyme in the newborn whose pancreatic function is immature. Milk from mothers delivering premature infants (preterm milk) has similar levels of BSSL activity to that of mothers of term infants (term milk). This study has determined whether the BSSL in preterm milk has the same characteristics as that in term milk. Milk samples were collected during the first 12 wk of lactation from seven mothers of infants born at 26-30 wk (very preterm, VPT), 31-37 wk (preterm, PT) and 37-42 wk (term, T) gestation. BSSL activity was measured using /sup 3/H-triolein emulsion as substrate. Time course, bile salt and enzyme concentration, pH and pH stability were studied, as well as inhibition of BSSL by eserine. The characteristics of BSSL from preterm and term milk were identical as were comparisons between colostrum and mature milk BSSL. BSSL from all milk sources had a neutral-to-alkaline pH optimum (pH 7.3-8.9), was stable at low pH for 60 min, and was 95-100% inhibited by eserine (greater than or equal to 0.6 mM). BSSL activity, regardless of enzyme source, was bile-salt dependent and was stimulated only by primary bile salts (taurocholate, glycocholate). The data indicate that the BSSL in milks of mothers delivering as early as 26 wk gestation is identical to that in term milk.

  12. Bile salts disrupt human esophageal squamous epithelial barrier function by modulating tight junction proteins.

    PubMed

    Chen, Xin; Oshima, Tadayuki; Shan, Jing; Fukui, Hirokazu; Watari, Jiro; Miwa, Hiroto

    2012-07-15

    Reflux of acid and bile acids contributes to epithelial tissue injury in gastro-esophageal reflux disease. However, the influence of refluxed material on human esophageal stratified epithelial barrier function and tight junction (TJ) proteins has not been fully elucidated. Here, we investigated the influence of acid and bile acids on barrier function and TJ protein distribution using a newly developed air-liquid interface (ALI) in vitro culture model of stratified squamous epithelium based on primary human esophageal epithelial cells (HEECs). Under ALI conditions, HEECs formed distinct epithelial layers on Transwell inserts after 7 days of culture. The epithelial layers formed TJ, and the presence of claudin-1, claudin-4, and occludin were detected by immunofluorescent staining. The NP-40-insoluble fraction of these TJ proteins was significantly higher by day 7 of ALI culture. Exposure of HEECs to pH 2, and taurocholic acid (TCA) and glycocholic acid (GCA) at pH 3, but not pH 4, for 1 h decreased transepithelial electrical resistance (TEER) and increased paracellular permeability. Exposure of cell layers to GCA (pH 3) and TCA (pH 3) for 1 h also markedly reduced the insoluble fractions of claudin-1 and -4. We found that deoxycholic acid (pH 7.4 or 6, 1 h) and pepsin (pH 3, 24 h) significantly decreased TEER and increased permeability. Based on these findings, ALI-cultured HEECs represent a new in vitro model of human esophageal stratified epithelium and are suitable for studying esophageal epithelial barrier functions. Using this model, we demonstrated that acid, bile acids, and pepsin disrupt squamous epithelial barrier function partly by modulating TJ proteins. These results provide new insights into understanding the role of TJ proteins in esophagitis.

  13. Bile salt metabolism in tropical sprue

    PubMed Central

    Bevan, G.; Engert, R.; Klipstein, F. A.; Maldonado, N.; Rubulis, A.; Turner, M. D.

    1974-01-01

    Mean and peak jejunal bile salt concentrations during digestion of a standard fat meal were found to be significantly lower in six Puerto Rican patients with untreated tropical sprue, all of whom had steatorrhoea, than in six asymptomatic subjects who had normal fat absorption. Bile salt pool size and turnover time did not differ significantly in the two groups. It is suggested that bile salt concentrations may be reduced in the proximal small intestine of patients with tropical sprue as a result of excessive dilution by intestinal fluid. The finding of low bile salt concentrations in two asymptomatic subjects indicates that bile salt lack alone may not be sufficient to produce steatorrhoea. PMID:4834549

  14. The effect of bile salts on carbonic anhydrase.

    PubMed

    Milov, D E; Jou, W S; Shireman, R B; Chun, P W

    1992-02-01

    Bile salts are potent inhibitors of bovine carbonic anhydrase and human carbonic anhydrase I and human carbonic anhydrase II. To further characterize the binding of bile salts to carbonic anhydrase, rate constants for the CO2 hydration reaction in the presence of deoxycholate, cholate, glycocholate and taurocholate were determined using stop-flow experiments. Values for the Michaelis-Menton dissociation constant for bovine carbonic anhydrase, human carbonic anhydrase I and human carbonic anhydrase II were found to be 5.2, 9.2 and 13.2 mmol/L, respectively. The inhibition constant values for the various bile salts tested ranged from 0.1 to 1 mmol/L for bovine carbonic anhydrase, 1.6 to 2.4 mmol/L for human carbonic anhydrase I and 0.09 to 0.7 mmol/L for human carbonic anhydrase II. Our results suggest a mechanism of noncompetitive carbonic anhydrase inhibition for bile salts. Bile-salt binding to carbonic anhydrases as measured by scanning molecular sieve chromatography resulted in an increase in partition radius, molecular volume and surface area. The partition radius increased from 24 A to 28 A in the presence of 2.5 mmol/L sodium deoxycholate at critical micelle concentration. As determined by sedimentation equilibrium measurements, approximately 1 gm of carbonic anhydrase will bind 0.03 gm of deoxycholate, suggesting three to six binding sites for bile salt on the carbonic anhydrase molecule. The conformational changes and inhibition of carbonic anhydrases resulting from bile-salt binding may be important to the regulation of enzymatic activity in tissues along the enterohepatic circulation; by limiting bicarbonate availability this interaction may also contribute to the metabolic derangements seen in patients with cholestatic liver disease. PMID:1735532

  15. Bile

    MedlinePlus

    ... the digestive tract. Bile contains mostly cholesterol, bile acids (also called bile salts), and bilirubin (a breakdown product of red blood cells). It also contains: Water Body salts (such as potassium and sodium) Copper ...

  16. The structure of truncated recombinant human bile salt-stimulated lipase reveals bile salt-independent conformational flexibility at the active-site loop and provides insights into heparin binding.

    PubMed

    Moore, S A; Kingston, R L; Loomes, K M; Hernell, O; Bläckberg, L; Baker, H M; Baker, E N

    2001-09-21

    Human bile salt-stimulated lipase (BSSL), which is secreted from the pancreas into the digestive tract and from the lactating mammary gland into human milk, is important for the effective absorption of dietary lipids. The dependence of BSSL on bile acids for activity with water-insoluble substrates differentiates it from other lipases. We have determined the crystal structure of a truncated variant of human BSSL (residues 1-5.8) and refined it at 2.60 A resolution, to an R-factor of 0.238 and R(free) of 0.275. This variant lacks the C-terminal alpha-helix and tandem C-terminal repeat region of native BSSL, but retains full catalytic activity. A short loop (residues 115-126) capable of occluding the active-site (the active site loop) is highly mobile and exists in two conformations, the most predominant of which leaves the active-site open for interactions with substrate. The bile salt analogue 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonic acid (CHAPS) was present in the crystallisation medium, but was not observed bound to the enzyme. However, the structure reveals a sulfonate group from the buffer piperizine ethane sulfonic acid (PIPES), making interactions with Arg63 and His115. His115 is part of the active-site loop, indicating that the loop could participate in the binding of a sulphate group from either the glycosaminoglycan heparin (known to bind BSSL) or a bile acid such as deoxycholate. Opening of the 115-126 active-site loop may be cooperatively linked to a sulphate anion binding at this site. The helix bundle domain of BSSL (residues 319-398) exhibits weak electron density and high temperature factors, indicating considerable structural mobility. This domain contains an unusual Asp:Glu pair buried in a hydrophobic pocket between helices alpha(H) and alpha(K) that may be functionally important. We have also solved the structure of full-length glycosylated human BSSL at 4.1 A resolution, using the refined coordinates of the truncated molecule as

  17. Mitigating the inhibition of human bile salt export pump by drugs: opportunities provided by physicochemical property modulation, in silico modeling, and structural modification.

    PubMed

    Warner, Daniel J; Chen, Hongming; Cantin, Louis-David; Kenna, J Gerry; Stahl, Simone; Walker, Clare L; Noeske, Tobias

    2012-12-01

    The human bile salt export pump (BSEP) is a membrane protein expressed on the canalicular plasma membrane domain of hepatocytes, which mediates active transport of unconjugated and conjugated bile salts from liver cells into bile. BSEP activity therefore plays an important role in bile flow. In humans, genetically inherited defects in BSEP expression or activity cause cholestatic liver injury, and many drugs that cause cholestatic drug-induced liver injury (DILI) in humans have been shown to inhibit BSEP activity in vitro and in vivo. These findings suggest that inhibition of BSEP activity by drugs could be one of the mechanisms that initiate human DILI. To gain insight into the chemical features responsible for BSEP inhibition, we have used a recently described in vitro membrane vesicle BSEP inhibition assay to quantify transporter inhibition for a set of 624 compounds. The relationship between BSEP inhibition and molecular physicochemical properties was investigated, and our results show that lipophilicity and molecular size are significantly correlated with BSEP inhibition. This data set was further used to build predictive BSEP classification models through multiple quantitative structure-activity relationship modeling approaches. The highest level of predictive accuracy was provided by a support vector machine model (accuracy = 0.87, κ = 0.74). These analyses highlight the potential value that can be gained by combining computational methods with experimental efforts in early stages of drug discovery projects to minimize the propensity of drug candidates to inhibit BSEP.

  18. Solubilization and Interaction Studies of Bile Salts with Surfactants and Drugs: a Review.

    PubMed

    Malik, Nisar Ahmad

    2016-05-01

    In this review, bile salt, bile salt-surfactant, and bile salt-drug interactions and their solubilization studies are mainly focused. Usefulness of bile salts in digestion, absorption, and excretion of various compounds and their rare properties in ordering the shape and size of the micelles owing to the presence of hydrophobic and hydrophilic faces are taken into consideration while compiling this review. Bile salts as potential bio-surfactants to solubilize drugs of interest are also highlighted. This review will give an insight into the selection of drugs in different applications as their properties get modified by interaction with bile salts, thus influencing their solution behavior which, in turn, modifies the phase-forming behavior, microemulsion, and clouding phenomenon, besides solubilization. Finally, their future perspectives are taken into consideration to assess their possible uses as bio-surfactants without side effects to human beings.

  19. Early Identification of Clinically Relevant Drug Interactions With the Human Bile Salt Export Pump (BSEP/ABCB11)

    PubMed Central

    Artursson, Per

    2013-01-01

    A comprehensive analysis was performed to investigate how inhibition of the human bile salt export pump (BSEP/ABCB11) relates to clinically observed drug-induced liver injury (DILI). Inhibition of taurocholate (TA) transport was investigated in BSEP membrane vesicles for a data set of 250 compounds, and 86 BSEP inhibitors were identified. Structure-activity modeling identified BSEP inhibition to correlate strongly with compound lipophilicity, whereas positive molecular charge was associated with a lack of inhibition. All approved drugs in the data set (n = 182) were categorized according to DILI warnings in drug labels issued by the Food and Drug Administration, and a strong correlation between BSEP inhibition and DILI was identified. As many as 38 of the 61 identified BSEP inhibitors were associated with severe DILI, including 9 drugs not previously linked to BSEP inhibition. Further, among the tested compounds, every second drug associated with severe DILI was a BSEP inhibitor. Finally, sandwich-cultured human hepatocytes (SCHH) were used to investigate the relationship between BSEP inhibition, TA transport, and clinically observed DILI in detail. BSEP inhibitors associated with severe DILI greatly reduced the TA canalicular efflux, whereas BSEP inhibitors with less severe or no DILI resulted in weak or no reduction of TA efflux in SCHH. This distinction illustrates the usefulness of SCHH in refined analysis of BSEP inhibition. In conclusion, BSEP inhibition in membrane vesicles was found to correlate to DILI severity, and altered disposition of TA in SCHH was shown to separate BSEP inhibitors associated with severe DILI from those with no or mild DILI. PMID:24014644

  20. Amylase activity in human bile.

    PubMed

    Donaldson, L A; Joffe, S N; McIntosh, W; Brodie, M J

    1979-03-01

    The mean amylase level in 42 human bile samples was 154 IU/l and there was no significant difference in the amylase activity of 32 paired serum and bile samples. Estimation of the amylase thermolability of bile showed it to be similar to that of serum. This suggests that the amylase activity in bile may have filtered through the liver from the hepatic circulation rather than refluxed from the pancreatic duct. The presence of amylase in human bile provides further evidence that the liver might have a role in the regulation of serum amylase.

  1. Are serum bile salt concentrations raised in hyperlipidaemia?

    PubMed Central

    Beckett, G J; Douglas, J G; Finlayson, N D; Percy-Robb, I W

    1980-01-01

    We have studied serum fasting and postprandial primary bile salt concentrations in a group of 10 consecutive hyperlipidaemic subjects. The efficiency of hepatic bile salt clearance in the same subjects was aslo studied using an injected dose of sodium glycocholate. No increase in serum fasting or postprandial concentrations of the primary bile salts were observed and hepatic bile salt clearance was only marginally abnormal in one subject. The presence of hyperlipidaemia does not invalidate the use of serum conjugated bile salt analysis for the detection of liver diseases. PMID:7399323

  2. Macitentan does not interfere with hepatic bile salt transport.

    PubMed

    Treiber, Alexander; Äänismaa, Päivi; de Kanter, Ruben; Delahaye, Stephane; Treher, Marianne; Hess, Patrick; Sidharta, Patricia

    2014-07-01

    Treatment of pulmonary arterial hypertension with the endothelin receptor antagonist bosentan has been associated with transient increases in liver transaminases. Mechanistically, bosentan inhibits the bile salt export pump (BSEP) leading to an intrahepatic accumulation of cytotoxic bile salts, which eventually results in hepatocellular damage. BSEP inhibition by bosentan is amplified by its accumulation in the liver as bosentan is a substrate of organic anion-transporting polypeptide (OATP) transport proteins. The novel endothelin receptor antagonist macitentan shows a superior liver safety profile. Introduction of the less acidic sulfamide moiety and increased lipophilicity yield a hepatic disposition profile different from other endothelin receptor antagonists. Passive diffusion rather than OATP-mediated uptake is the driving force for macitentan uptake into the liver. Interaction with the sodium taurocholate cotransporting polypeptide and BSEP transport proteins involved in hepatic bile salt homeostasis is therefore limited due to the low intrahepatic drug concentrations. Evidence for this conclusion is provided by in vitro experiments in drug transporter-expressing cell lines, acute and long-term studies in rats and dogs, absence of plasma bile salt changes in healthy human volunteers after multiple dosing, and finally the liver safety profile of macitentan in the completed phase III morbidity/mortality SERAPHIN (Study with an Endothelin Receptor Antagonist in Pulmonary Arterial Hypertension to Improve Clinical Outcome) trial.

  3. Bile salt-membrane interactions and the physico-chemical mechanisms of bile salt toxicity.

    PubMed

    Heuman, D M

    1995-09-01

    We present evidence that ursodeoxycholate prevents toxicity of more hydrophobic bile salts by inhibiting micellar solubilization of membrane lipids. Using both centrifugal ultrafiltration and gel filtration methods we studied leakage of inulin from vesicles composed of egg phosphatidylcholine and cholesterol. We observed that the addition of tauroursodeoxycholate to taurodeoxycholate reduced leakage of inulin from large unilamelar vesicles compared to that seen with taurodeoxycholate alone. This protective effect was observed only at high membrane cholesterol:phospholipid ratios (> or = 0.5). By gel filtration we found that fractional leakage of inulin from vesicles was identical to fractional phospholipid solubilization, indicating that release of inulin from vesicles results from membrane dissolution rather than from increased permeability of otherwise intact membranes. Addition of tauroursodeoxycholate to taurodeoxycholate was found to suppress the dissolution of phospholipid from cholesterol-rich vesicles. Bile salts were found to absorb to vesicles with an affinity proportional to their relative hydrophobicity, as estimated by reverse phase HPLC. Adsorption affinity decreased progressively with increasing membrane cholesterol content. Different bile salts displaced each other from membranes in proportion to their respective binding, affinities. Tauroursodeoxycholate, which absorbed to membranes with low affinity, displaced taurodeoxycholate from vesicles only weakly. Based on these findings we postulate that bile salts may damage the liver through solubilization of canalicular membrane lipids. Ursodeoxycholate may protect the liver by inhibiting dissolution of the cholesterol-rich canalicular membrane by more hydrophobic endogenous bile salts. Biliary secretion of vesicles rich in phosphatidylcholine may buffer the intermicellar concentration of bile acids at levels below those required to disrupt the cholesterol-rich canalicular membrane; thus biliary vesicle

  4. The sodium bile salt cotransport family SLC10.

    PubMed

    Hagenbuch, Bruno; Dawson, Paul

    2004-02-01

    The SLC10 family of sodium/bile salt cotransporters contains over 50 members in animal, plant and bacterial species. In man, two well-characterized members and three orphan transporters are known. The Na(+)/taurocholate cotransporting polypeptide (NTCP; SLC10A1) and the apical sodium-dependent bile salt transporter (ASBT; SLC10A2) are critical components of the enterohepatic circulation of bile salts. NTCP and ASBT are cotransporters that mediate sodium-dependent, electrogenic uptake of mainly bile salts into hepatocytes (NTCP), biliary epithelial cells, ileal enterocytes and renal proximal tubular cells (ASBT).

  5. A New Insight into the Physiological Role of Bile Salt Hydrolase among Intestinal Bacteria from the Genus Bifidobacterium

    PubMed Central

    Jarocki, Piotr; Podleśny, Marcin; Glibowski, Paweł; Targoński, Zdzisław

    2014-01-01

    This study analyzes the occurrence of bile salt hydrolase in fourteen strains belonging to the genus Bifidobacterium. Deconjugation activity was detected using a plate test, two-step enzymatic reaction and activity staining on a native polyacrylamide gel. Subsequently, bile salt hydrolases from B. pseudocatenulatum and B. longum subsp. suis were purified using a two-step chromatographic procedure. Biochemical characterization of the bile salt hydrolases showed that the purified enzymes hydrolyzed all of the six major human bile salts under the pH and temperature conditions commonly found in the human gastrointestinal tract. Next, the dynamic rheometry was applied to monitor the gelation process of deoxycholic acid under different conditions. The results showed that bile acids displayed aqueous media gelating properties. Finally, gel-forming abilities of bifidobacteria exhibiting bile salt hydrolase activity were analyzed. Our investigations have demonstrated that the release of deconjugated bile acids led to the gelation phenomenon of the enzymatic reaction solution containing purified BSH. The presented results suggest that bile salt hydrolase activity commonly found among intestinal microbiota increases hydrogel-forming abilities of certain bile salts. To our knowledge, this is the first report showing that bile salt hydrolase activity among Bifidobacterium is directly connected with the gelation process of bile salts. In our opinion, if such a phenomenon occurs in physiological conditions of human gut, it may improve bacterial ability to colonize the gastrointestinal tract and their survival in this specific ecological niche. PMID:25470405

  6. Bile salt hydrophobicity controls vesicle secretion rates and transformations in native bile.

    PubMed

    Cohen, D E; Leighton, L S; Carey, M C

    1992-09-01

    After drainage of the bile salt pool, we infused unanesthetized bile fistula prairie dogs (Cynomys ludovicianus) intravenously with taurine-conjugated chenodeoxycholate (TCDC), cholate (TC), ursodeoxycholate (TUDC), and ursocholate (TUC) in concentrations that attained greater than 94% enrichment of biliary bile salts. With decreases in bile salt hydrophobicity, maximum steady state lecithin and to a lesser extent cholesterol secretion rates decreased in the rank order, TCDC greater than TC greater than TUDC greater than TUC. By phase analysis, TCDC-rich and TC-rich biles plotted inside their respective micellar zones, whereas TUDC-rich and TUC-rich biles plotted outside and were so-called "supersaturated" with cholesterol. Quasi-elastic light scattering and electron microscopy, when performed within 30 min of collection, revealed unilamellar vesicles in all biles. By 24 h, vesicles in TCDC-rich and TC-rich biles had dissolved into mixed micelles, whereas vesicles in TUDC-rich biles formed mixed micelles plus multilamellar liquid crystals, and vesicles in TUC-rich biles formed multilamellar liquid crystals exclusively. Because cholesterol/phospholipid molar ratios of multilamellar liquid crystals were less than or equal to 1, cholesterol monohydrate crystals did not form in these biles. We conclude that, despite drastic alterations in bile salt detergency, unilamellar vesicles are the final common pathway for lecithin and cholesterol secretion into bile. During equilibration of bile, the fate of unilamellar vesicles may be micellar, micellar plus liquid crystalline, or liquid crystalline only depending on the detergency (i.e., hydrophobic-hydrophilic balance) of the secreted bile salt.

  7. Quantification of Cholesterol Solubilized in Dietary Micelles: Dependence on Human Bile Salt Variability and the Presence of Dietary Food Ingredients.

    PubMed

    Coreta-Gomes, Filipe M; Vaz, Winchil L C; Wasielewski, Emeric; Geraldes, Carlos F G; Moreno, Maria João

    2016-05-10

    The solubility of cholesterol in bile salt (BS) micelles is important to understand the availability of cholesterol for absorption in the intestinal epithelium and to develop strategies to decrease cholesterol intake from the intestinal lumen. This has been the subject of intense investigation, due to the established relation between the development of diseases such as atherosclerosis and high levels of cholesterol in the blood. In this work we quantify the effect of BS variability on the amount of cholesterol solubilized. The effect of some known hypocholesterolemic agents usually found in the diet is also evaluated, as well as some insight regarding the mechanisms involved. The results show that, depending on the bile salt composition, the average value of sterol per micelle is equal to or lower than 1. The amount of cholesterol solubilized in the BS micelles is essentially equal to its total concentration until the solubility limit is reached. Altogether, this indicates that the maximum cholesterol solubility in the BS micellar solution is the result of saturation of the aqueous phase and depends on the partition coefficient of cholesterol between the aqueous phase and the micellar pseudophase. The effect on cholesterol maximum solubility for several food ingredients usually encountered in the diet was characterized using methodology developed recently by us. This method allows the simultaneous quantification of both cholesterol and food ingredient solubilized in the BS micelles even in the presence of larger aggregates, therefore avoiding their physical separation with possible impacts on the overall equilibrium. The phytosterols stigmasterol and stigmastanol significantly decreased cholesterol solubility with a concomitant reduction in the total amount of sterol solubilized, most pronounced for stigmasterol. Those results point toward coprecipitation being the major cause for the decrease in cholesterol solubilization by the BS micelles. The presence of

  8. Bile salts act as effective protein-unfolding agents and instigators of disulfide stress in vivo

    PubMed Central

    Cremers, Claudia M.; Knoefler, Daniela; Vitvitsky, Victor; Banerjee, Ruma; Jakob, Ursula

    2014-01-01

    Commensal and pathogenic bacteria must deal with many different stress conditions to survive in and colonize the human gastrointestinal tract. One major challenge that bacteria encounter in the gut is the high concentration of bile salts, which not only aid in food absorption but also act as effective physiological antimicrobials. The mechanism by which bile salts limit bacterial growth is still largely unknown. Here, we show that bile salts cause widespread protein unfolding and aggregation, affecting many essential proteins. Simultaneously, the bacterial cytosol becomes highly oxidizing, indicative of disulfide stress. Strains defective in reducing oxidative thiol modifications, restoring redox homeostasis, or preventing irreversible protein aggregation under disulfide stress conditions are sensitive to bile salt treatment. Surprisingly, cholate and deoxycholate, two of the most abundant and very closely related physiological bile salts, vary substantially in their destabilizing effects on proteins in vitro and cause protein unfolding of different subsets of proteins in vivo. Our results provide a potential mechanistic explanation for the antimicrobial effects of bile salts, help explain the beneficial effects of bile salt mixtures, and suggest that we have identified a physiological source of protein-unfolding disulfide stress conditions in bacteria. PMID:24706920

  9. Interaction of uncharged bile salt derivatives with the ileal bile salt transport system.

    PubMed

    Bundy, R; Mauskopf, J; Walker, J T; Lack, L

    1977-05-01

    Two series of uncharged conjugated bile salt derivatives, N-conjugates of ethanolamine and 3-amino-1,2-propanediol were studied for interaction with the ileal bile salt transport system. Evidence for interaction is threefold. 1) In everted gut sac experiments more material was removed from the mucosal compartment when ileal sacs were used. 2) These derivatives inhibited the in vitro transport of taurocholate. 3) In vivo intestinal perfusion demonstrated greater absorption from ileum than from jejunum. Number three demonstrates that such interactions are followed by transmucosal movement. Their uphill transport was less than taurocholate transport. The Na(+) requirement for cholyl-3-amino-1,2-propanediol interaction with the system was greater than for taurocholate. This observation is similar to that previously observed with taurodehydrocholate, which had a greater Na(+) requirement for transport than taurocholate. Therefore removal of the anionic charge, as well as distortion of steroid shape, increases the Na(+) requirement for substrate interaction with the transport system. These observations support our hypothesis that this interaction involves two recognition components; one includes the steroid moiety, the other a coulombic interaction between the anionic bile salt and a cationic membrane site. Additionally the membrane would have an anionic group to accomodate the Na(+). Both factors (steroidal and coulombic) operate for optimal substrate attachment. Simultaneously the system's affinity for Na(+) increases and active transport then proceeds.

  10. Deconjugated Bile Salts Produced by Extracellular Bile-Salt Hydrolase-Like Activities from the Probiotic Lactobacillus johnsonii La1 Inhibit Giardia duodenalis In vitro Growth

    PubMed Central

    Travers, Marie-Agnès; Sow, Cissé; Zirah, Séverine; Deregnaucourt, Christiane; Chaouch, Soraya; Queiroz, Rayner M. L.; Charneau, Sébastien; Allain, Thibault; Florent, Isabelle; Grellier, Philippe

    2016-01-01

    Giardiasis, currently considered a neglected disease, is caused by the intestinal protozoan parasite Giardia duodenalis and is widely spread in human as well as domestic and wild animals. The lack of appropriate medications and the spread of resistant parasite strains urgently call for the development of novel therapeutic strategies. Host microbiota or certain probiotic strains have the capacity to provide some protection against giardiasis. By combining biological and biochemical approaches, we have been able to decipher a molecular mechanism used by the probiotic strain Lactobacillus johnsonii La1 to prevent Giardia growth in vitro. We provide evidence that the supernatant of this strain contains active principle(s) not directly toxic to Giardia but able to convert non-toxic components of bile into components highly toxic to Giardia. By using bile acid profiling, these components were identified as deconjugated bile-salts. A bacterial bile-salt-hydrolase of commercial origin was able to mimic the properties of the supernatant. Mass spectrometric analysis of the bacterial supernatant identified two of the three bile-salt-hydrolases encoded in the genome of this probiotic strain. These observations document a possible mechanism by which L. johnsonii La1, by secreting, or releasing BSH-like activity(ies) in the vicinity of replicating Giardia in an environment where bile is present and abundant, can fight this parasite. This discovery has both fundamental and applied outcomes to fight giardiasis, based on local delivery of deconjugated bile salts, enzyme deconjugation of bile components, or natural or recombinant probiotic strains that secrete or release such deconjugating activities in a compartment where both bile salts and Giardia are present. PMID:27729900

  11. Studies of feedback suppression of bile salt synthesis in the bile-fistula rat.

    PubMed

    Duane, W C; McHale, A P; Hamilton, J N

    1988-02-01

    We have previously reported that intravenous infusion of taurocholate at 10 mumol (100 g.hr) into bile-fistula rats suppressed bile salt synthesis by 85% (Pries et al. 1983. J. Lipid Res. 24: 141-146). Recently, however, infusion rates twice this high have been reported not to suppress synthesis (Davis et al. 1984. Falk Symposium 42. MTP Press Ltd., Boston. 37-45). Because the only major difference in design of these two studies was supplementation with sodium bicarbonate to replace biliary losses induced by bile salt choleresis, we have repeated our studies with and without bicarbonate supplementation. Without bicarbonate, as before, we found suppression of synthesis during infusion of taurocholate at 10 mumol/(100 g.hr). With bicarbonate, no suppression of synthesis occurred at these infusion rates. These data indicate that bicarbonate supplementation is essential when testing physiological effects of infused bile salt in the bile-fistula rat. PMID:2835417

  12. Regulation of Bile Salt Transport in Rat Liver

    PubMed Central

    Simon, Francis R.; Sutherland, Eileen M.; Gonzalez, Manuel

    1982-01-01

    Expansion of the bile salt pool size in rats increases maximum excretory capacity for taurocholate. We examined whether increased bile salt transport is due to recruitment of centrolobular transport units or rather to adaptive changes in the hepatocyte. Daily sodium cholate (100 mg/100 g body wt) was administered orally to rats. This treatment was well tolerated for at least 4 d and produced an 8.2-fold expansion of the bile salt pool. This expanded pool consisted predominently (99%) of cholic and deoxycholic acids. Significantly increased bile salt transport was not observed until 16 h after bile acid loading, and maximum elevations of transport capacity to 2.3-fold of control required ∼2 d. In contrast, maximum sulfobromophthalein excretion rates increased 2.2-fold as early as 4 h and actually fell to 1.5-fold increase at 4 d. We studied the possibility that this adaptive increase in bile salt secretory transport was due to changes in canalicular surface membrane area, lipid composition, or increased number of putative carriers. Canalicular membrane protein recovery and the specific activities of leucine aminopeptidase, Mg++-ATPase and 5′-nucleotidase activities were unaltered by bile salt pool expansion. The content of free and esterified cholesterol and total phospholipids was unchanged in liver surface membrane fractions compared with control values. In contrast, sodium cholate administration selectively increased specific [14C]cholic acid binding sites twofold in liver surface membrane fractions. Increased numbers of [14C]cholic acid receptors (a) was associated with the time-dependent increase in bile salt transport, and (b) was selective for the taurine conjugate of cholate and (c) was reduced by chenodeoxycholate. Changes in bile acid binding sites 16 h following taurocholate and chenodeoxycholate and the lack of change with glycocholate was associated with comparable changes in bile salt transport. In conclusion, selective bile salts increase bile

  13. Consequences of bile salt biotransformations by intestinal bacteria.

    PubMed

    Ridlon, Jason M; Harris, Spencer C; Bhowmik, Shiva; Kang, Dae-Joong; Hylemon, Phillip B

    2016-01-01

    Emerging evidence strongly suggest that the human "microbiome" plays an important role in both health and disease. Bile acids function both as detergents molecules promoting nutrient absorption in the intestines and as hormones regulating nutrient metabolism. Bile acids regulate metabolism via activation of specific nuclear receptors (NR) and G-protein coupled receptors (GPCRs). The circulating bile acid pool composition consists of primary bile acids produced from cholesterol in the liver, and secondary bile acids formed by specific gut bacteria. The various biotransformation of bile acids carried out by gut bacteria appear to regulate the structure of the gut microbiome and host physiology. Increased levels of secondary bile acids are associated with specific diseases of the GI system. Elucidating methods to control the gut microbiome and bile acid pool composition in humans may lead to a reduction in some of the major diseases of the liver, gall bladder and colon. PMID:26939849

  14. Dissolution rate of griseofulvin in bile salt solutions.

    PubMed

    de Smidt, J H; Offringa, J C; Crommelin, D J

    1991-04-01

    Bile salts increase the apparent solubility of lipophilic poorly water-soluble drugs like griseofulvin. In this study, the dissolution kinetics of griseofulvin in solutions of bile salts (sodium taurocholate and sodium cholate) were investigated. A rotating disk apparatus was chosen to monitor dissolution kinetics; it well-defined hydrodynamic conditions allowed for analysis of the behavior of bile salt micelles under different conditions. Griseofulvin solubility and dissolution rate increased with increasing bile salt concentration in the dissolution medium. The enhancement of the dissolution rate was not linearly related to the solubility increase, as diffusional transport of the solubilized drug proved to be less efficient than transport of the unsolubilized ("free") drug. The dissolution process proved to be controlled by convective diffusion. An analysis of the data with the phase separation model provided results for the micellar diffusion coefficient comparable with literature data obtained with different techniques. PMID:1865343

  15. Total protein output during rapid reduction of bile salt secretion rates in man.

    PubMed Central

    Harvey, P R; Toth, J L; Upadhya, G A; Ilson, R G; Strasberg, S M

    1989-01-01

    An investigation was undertaken to study the effect of bile salt secretion on total biliary protein secretion in man. Bile was collected in eight patients from a tube in the bile duct. Collection was started after a meal and continued for six hours, in order to obtain bile salt secretion rates over the entire physiological range. Total protein secretion rates did not vary with change in bile salt secretion or bile flow. The protein pattern assessed by SDS-PAGE did not vary with bile salt secretion. The results indicate that bile salt secretion has little influence on biliary protein secretion under these conditions in man. Changes in bile salt secretion were associated with linear change in bile flow, but there was no relationship between bile flow and protein secretion rates. This argues against convective sieving of plasma proteins into bile. Images Fig. 4 PMID:2920916

  16. Alterations in nanoparticle protein corona by biological surfactants: impact of bile salts on β-lactoglobulin-coated gold nanoparticles.

    PubMed

    Winuprasith, Thunnalin; Chantarak, Sirinya; Suphantharika, Manop; He, Lili; McClements, David Julian

    2014-07-15

    The impact of biological surfactants (bile salts) on the protein (β-lactoglobulin) corona surrounding gold nanoparticles (200 nm) was studied using a variety of analytical techniques at pH 7: dynamic light scattering (DLS); particle electrophoresis (ζ-potential); UV-visible (UV) spectroscopy; transmission electron microscopy (TEM); and surface-enhanced Raman scattering (SERS). The bile salts adsorbed to the protein-coated nanoparticle surfaces and altered their interfacial composition, charge, and structure. SERS spectra of protein-coated nanoparticles after bile salt addition contained bands from both protein and bile salts, indicating that the protein was not fully displaced by the bile salts. UV, DLS and TEM techniques also indicated that the protein coating was not fully displaced from the nanoparticle surfaces. The impact of bile salts could be described by an orogenic mechanism: mixed interfaces were formed that consisted of islands of aggregated proteins surrounded by a sea of bile salts. This knowledge is useful for understanding the interactions of bile salts with protein-coated colloidal particles, which may be important for controlling the fate of colloidal delivery systems in the human gastrointestinal tract, or the gastrointestinal fate of ingested inorganic nanoparticles.

  17. Importance of bicarbonate in bile salt independent fraction of bile flow.

    PubMed

    Hardison, W G; Wood, C A

    1978-08-01

    The bile salt independent fraction (BSIF) of canalicular bile flow from the isolated rat liver perfused with bicarbonate-free perfusate is 50% of that from the liver perfused with bicarbonate-containing perfusate. HCO3-excretion is nearly eliminated and Na+ and Cl- excretion is reduced 50%. Replacement of HCO3- into perfusate increased bile flow by 0.3 microliter/g.min without changing bile acid excretion rate. 5.5-Dimethyl-2,4-oxazolidinedione (DMO) produced a similar effect. DMO was passively distributed between bile and plasma. The data indicate that a bicarbonate transport mechanism is responsible for production of up to 50% of the BSIF. Another weak acid, N-5[5-(2-methoxyethoxy)-2-pyrimidinyl]sulfamoylbenzene (glymidine), was rapidly excreted into bile and increased bile flow by over 2.0 microliter/g.min. Glymidine is probably excreted by an independent organic anion transport mechanism, and any effect on the bicarbonate transport mechanism is obscured. Canaliculus-enriched hepatocyte membrane fractions contained no HCO3-stimulated ATPase activity. Either this enzyme is unimportant in hepatocyte bicarbonate transport or transport occurs across membranes other than the bile canalicular membrane. PMID:150796

  18. Bile salt receptor complex activates a pathogenic type III secretion system.

    PubMed

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N; Salomon, Dor; Tomchick, Diana R; Grishin, Nick V; Orth, Kim

    2016-01-01

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered that Vibrio parahaemolyticus VtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment. PMID:27377244

  19. Bile salt receptor complex activates a pathogenic type III secretion system

    PubMed Central

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N; Salomon, Dor; Tomchick, Diana R; Grishin, Nick V; Orth, Kim

    2016-01-01

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered that Vibrio parahaemolyticus VtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment. DOI: http://dx.doi.org/10.7554/eLife.15718.001 PMID:27377244

  20. Effects of taurodihydrofusidate, a bile salt analogue, on bile formation and biliary lipid secretion in the rhesus monkey.

    PubMed Central

    Beaudoin, M; Carey, M C; Small, D M

    1975-01-01

    Bile salts play a major role in bile formation and biliary lipid secretion. Sodium taurodihydrofusidate (TDHF), a derivative of the antibiotic fusidic acid, closely resembles bile salts in terms of structure, micellar characteristics, and capacity ot solubilize otherwise insolbule lipids. We have therefore studied the biliary secretion of this bile salt analogue and its influence on bile formation and biliary lipid secretion in primates. Alert, unanesthetized female rhesus monkeys prepared with a total biliary fistula were allowed to reach a steady bile salt secretion rate before each study. In three animals (group I),[14C]TDHF was infused intravenously. Most of the compound was secreted rapidly in bile chemically unchanged. The biliary secretion of this drug produced a twofold increase in bile flow; however, the bile salt output was markedly reduced during the infusion. In spite of this reduction, the phospholipid output remained essentially unchanged whereas the cholesterol output increased almost twofold. In five other animals (group II), the effect of TDHF on the bile salt secretion was further investigated by an intravenous infusion of [14C]taurocholate followed by a combined infusion of [14C]taurocholate and TDHF. When TDHF was added to the infusate, a reduction in the [14C]taurocholate output and a progressive rise in the plasma [14C]taurocholate concentration were observed in each animal. An analysis of the data in both groups indicates that (a) the most likely explanation to account for the decreased bile salt output is that the bile salt analogue, TDHF, interfered with bile salt secretion into the biliary canaliculi; (b) TDHF induces a greater secretion of biliary water than was observed with bile salts, an effect consistent with a stimulation of the bile salt-independent canalicular flow; (c) at similar 3alpha-hydroxysteroid secretion rates TDHF caused a significant increase in cholesterol secretion compared to that induced by bile salt. This finding

  1. Bile Salt Micelles and Phospholipid Vesicles Present in Simulated and Human Intestinal Fluids: Structural Analysis by Flow Field-Flow Fractionation/Multiangle Laser Light Scattering.

    PubMed

    Elvang, Philipp A; Hinna, Askell H; Brouwers, Joachim; Hens, Bart; Augustijns, Patrick; Brandl, Martin

    2016-09-01

    Knowledge about colloidal assemblies present in human intestinal fluids (HIFs), such as bile salt micelles and phospholipid vesicles, is regarded of importance for a better understanding of the in vivo dissolution and absorption behavior of poorly soluble drugs (Biopharmaceutics Classification System class II/IV drugs) because of their drug-solubilizing ability. The characterization of these potential drug-solubilizing compartments is a prerequisite for further studies of the mechanistic interplays between drug molecules and colloidal structures within HIFs. The aim of the present study was to apply asymmetrical flow field-flow fractionation (AF4) in combination with multiangle laser light scattering in an attempt to reveal coexistence of colloidal particles in both artificial and aspirated HIFs and to determine their sizes. Asymmetrical flow field-flow fractionation/multiangle laser light scattering analysis of the colloidal phase of intestinal fluids allowed for a detailed insight into the whole spectrum of submicron- to micrometer-sized particles. With respect to the simulated intestinal fluids mimicking fasted and fed state (FaSSIF-V1 and FeSSIF-V1, respectively), FaSSIF contained one distinct size fraction of colloidal assemblies, whereas FeSSIF contained 2 fractions of colloidal species with significantly different sizes. These size fractions likely represent (1) mixed taurocholate-phospholipid-micelles, as indicated by a size range up to 70 nm (in diameter) and a strong UV absorption and (2) small phospholipid vesicles of 90-210 nm diameter. In contrast, within the colloidal phase of the fasted state aspirate of a human volunteer, 4 different size fractions were separated from each other in a consistent and reproducible manner. The 2 fractions containing large particles showed mean sizes of approximately 50 and 200 nm, respectively (intensity-weighted mean diameter, Dz), likely representing mixed cholate/phospholipid micelles and phospholipid vesicles

  2. Isolation of a bile salt sulfatase-producing Clostridium strain from rat intestinal microflora.

    PubMed Central

    Huijghebaert, S M; Mertens, J A; Eyssen, H J

    1982-01-01

    Bile acid sulfates, formed in human and rat livers, are desulfated by the intestinal microflora. In our study we first isolated from conventional rat feces an unnamed bacterium, termed strain S1, which desulfated the 5 beta-bile salt 3 alpha-sulfates in vitro and in vivo after association with gnotobiotic rats. Strain S1 also possessed 12 alpha-hydroxysteroid dehydrogenase and bile salt-deconjugating activities. The strain was a strict anaerobic, CO2-requiring, gram-negative, sporeforming rod and was designated as belonging to the genus Clostridium. Growth was scarce in culture media, unless in the presence of 0.1% taurine, a sulfur-containing amino acid. Addition of this substance raised the number of bacteria in thioglycolate and peptone yeast media from 10(4) per ml to 10(6) to 10(7) per ml and increased the colony diameter on agar medium from 0.2 mm to 0.5 to 0.9 mm. Sulfatase activity was specific for the 5 beta-bile salt sulfates, leaving the 5 alpha-bile salt sulfates unchanged. In addition, the sulfatase activity was cell bound, and its production was dependent on the composition of the culture medium, although no minimal sulfur medium was required for sulfatase activity. Images PMID:7055372

  3. Ultracentrifugal isolation of vesicular carriers of biliary cholesterol in native human and rat bile.

    PubMed

    Ulloa, N; Garrido, J; Nervi, F

    1987-01-01

    We have utilized ultracentrifugation of native bile-Metrizamide density gradients to isolate a vesicular transport system of biliary lipids in both man and rat. We identified vesicular structures by electron microscopy. Fresh bile specimens were obtained from bile fistula rats (unsaturated bile) and from patients 1 week after bile duct surgery (supersaturated bile). Metrizamide was dissolved in bile (33% w/v), and continuous density gradients were performed with undiluted bile (density limits = 1.020 to 1.300 gm per ml). The relative distribution of biliary cholesterol, phospholipid and bile salt was studied as a function of the density of the fractions. Approximately 50% of total rat biliary cholesterol and between 61 and 90% of human biliary cholesterol was concentrated in the lightest fractions of the gradients (density less than 1.060 gm per ml). In contrast, less than 20% of bile salts was present in fractions with densities lower than 1.060 gm per ml. The highest amounts of bile salts and phospholipids of the bile-Metrizamide density gradients were found in the density range of 1.075 to 1.100 gm per ml in both human and rat bile. More than 80% of biliary proteins was found in fractions with densities greater than 1.075 gm per ml, and only 2% was found in the cholesterol-rich fraction with density less than 1.060 gm per ml in both species. When bile salt concentration was raised in rat bile from 38 to 97 mM by adding taurocholate, the low density cholesterol-rich fraction almost disappeared. Electron microscopy of negatively stained preparations of the fractions with density less than 1.060 gm per ml showed 40 to 120 nm vesicles, which were not apparent in the other fractions. Similar vesicles were demonstrated also in fresh rat bile and within the canaliculi after acute depletion of the bile salt pool (biliary bile salt concentration of 3.45 mM; total biliary lipid concentration of 0.25 gm%). The structure of these vesicles was shown in thin sections of liver

  4. In Sickness and in Health: The Relationships Between Bacteria and Bile in the Human Gut.

    PubMed

    Hay, A J; Zhu, J

    2016-01-01

    Colonization of a human host with a commensal microbiota has a complex interaction in which bacterial communities provide numerous health benefits to the host. An equilibrium between host and microbiota is kept in check with the help of biliary secretions by the host. Bile, composed primarily of bile salts, promotes digestion. It also provides a barrier between host and bacteria. After bile salts are synthesized in the liver, they are stored in the gallbladder to be released after food intake. The set of host-secreted bile salts is modified by the resident bacteria. Because bile salts are toxic to bacteria, an equilibrium of modified bile salts is reached that allows commensal bacteria to survive, yet rebuffs invading pathogens. In addition to direct toxic effects on cells, bile salts maintain homeostasis as signaling molecules, tuning the immune system. To cause disease, gram-negative pathogenic bacteria have shared strategies to survive this harsh environment. Through exclusion of bile, efflux of bile, and repair of bile-induced damage, these pathogens can successfully disrupt and outcompete the microbiota to activate virulence factors. PMID:27565580

  5. Bile salts of vertebrates: structural variation and possible evolutionary significance[S

    PubMed Central

    Hofmann, Alan F.; Hagey, Lee R.; Krasowski, Matthew D.

    2010-01-01

    Biliary bile salt composition of 677 vertebrate species (103 fish, 130 reptiles, 271 birds, 173 mammals) was determined. Bile salts were of three types: C27 bile alcohols, C27 bile acids, or C24 bile acids, with default hydroxylation at C-3 and C-7. C27 bile alcohols dominated in early evolving fish and amphibians; C27 bile acids, in reptiles and early evolving birds. C24 bile acids were present in all vertebrate classes, often with C27 alcohols or with C27 acids, indicating two evolutionary pathways from C27 bile alcohols to C24 bile acids: a) a ‘direct’ pathway and b) an ‘indirect’ pathway with C27 bile acids as intermediates. Hydroxylation at C-12 occurred in all orders and at C-16 in snakes and birds. Minor hydroxylation sites were C-1, C-2, C-5, C-6, and C-15. Side chain hydroxylation in C27 bile salts occurred at C-22, C-24, C-25, and C-26, and in C24 bile acids, at C-23 (snakes, birds, and pinnipeds). Unexpected was the presence of C27 bile alcohols in four early evolving mammals. Bile salt composition showed significant variation between orders but not between families, genera, or species. Bile salt composition is a biochemical trait providing clues to evolutionary relationships, complementing anatomical and genetic analyses. PMID:19638645

  6. Inhibition of methanogenesis by human bile.

    PubMed Central

    Florin, T H; Woods, H J

    1995-01-01

    The factors that regulate methanogenesis in humans have not been established. The presence of bile acid, which is lost into the colon from the small intestine, may be an important regulatory factor of methanogenesis. To examine this possibility, the effect of human bile on methane production by faecal cultures, and the in vivo effect of biliary diversion on breath methane excretion in a methanogenic choledochostomy patient, were investigated. Faecal suspensions (0.1%) from five methanogenic humans were incubated anaerobically with bile (0.3-30%) from three choledochostomy patients, and headspace methane measured by gas chromatography. All biles inhibited headspace methane. Inhibition of methanogenesis was dose dependent, plateaued at 10-30% bile concentration, and was abolished by 0.6% cholestyramine. The maximum inhibition by bile, median (range), was 38 (0.9-56)% of control methane values. Reversal of the bile fistula in the fourth choledochostomy patient converted that subject from methanogenic to 'non-methanogenic' status, It is concluded that inhibition of methanogens in the caecum by bile acid could significantly reduce the number of methanogens in the colon. This and the effect of transit time could explain much of the known epidemiology of 'non-methanogenesis', which has been related to obesity, (comparatively) fast colonic transit in healthy persons, and to small intestinal Crohn's disease. PMID:7590441

  7. Analysis of the Bile Salt Export Pump (ABCB11) Interactome Employing Complementary Approaches

    PubMed Central

    Przybylla, Susanne; Stindt, Jan; Kleinschrodt, Diana; Schulte am Esch, Jan; Häussinger, Dieter; Keitel, Verena; Smits, Sander H.; Schmitt, Lutz

    2016-01-01

    The bile salt export pump (BSEP, ABCB11) plays an essential role in the formation of bile. In hepatocytes, BSEP is localized within the apical (canalicular) membrane and a deficiency of canalicular BSEP function is associated with severe forms of cholestasis. Regulation of correct trafficking to the canalicular membrane and of activity is essential to ensure BSEP functionality and thus normal bile flow. However, little is known about the identity of interaction partners regulating function and localization of BSEP. In our study, interaction partners of BSEP were identified in a complementary approach: Firstly, BSEP interaction partners were co-immunoprecipitated from human liver samples and identified by mass spectrometry (MS). Secondly, a membrane yeast two-hybrid (MYTH) assay was used to determine protein interaction partners using a human liver cDNA library. A selection of interaction partners identified both by MYTH and MS were verified by in vitro interaction studies using purified proteins. By these complementary approaches, a set of ten novel BSEP interaction partners was identified. With the exception of radixin, all other interaction partners were integral or membrane-associated proteins including proteins of the early secretory pathway and the bile acyl-CoA synthetase, the second to last, ER-associated enzyme of bile salt synthesis. PMID:27472061

  8. Analysis of the Bile Salt Export Pump (ABCB11) Interactome Employing Complementary Approaches.

    PubMed

    Przybylla, Susanne; Stindt, Jan; Kleinschrodt, Diana; Schulte Am Esch, Jan; Häussinger, Dieter; Keitel, Verena; Smits, Sander H; Schmitt, Lutz

    2016-01-01

    The bile salt export pump (BSEP, ABCB11) plays an essential role in the formation of bile. In hepatocytes, BSEP is localized within the apical (canalicular) membrane and a deficiency of canalicular BSEP function is associated with severe forms of cholestasis. Regulation of correct trafficking to the canalicular membrane and of activity is essential to ensure BSEP functionality and thus normal bile flow. However, little is known about the identity of interaction partners regulating function and localization of BSEP. In our study, interaction partners of BSEP were identified in a complementary approach: Firstly, BSEP interaction partners were co-immunoprecipitated from human liver samples and identified by mass spectrometry (MS). Secondly, a membrane yeast two-hybrid (MYTH) assay was used to determine protein interaction partners using a human liver cDNA library. A selection of interaction partners identified both by MYTH and MS were verified by in vitro interaction studies using purified proteins. By these complementary approaches, a set of ten novel BSEP interaction partners was identified. With the exception of radixin, all other interaction partners were integral or membrane-associated proteins including proteins of the early secretory pathway and the bile acyl-CoA synthetase, the second to last, ER-associated enzyme of bile salt synthesis. PMID:27472061

  9. Investigating bile salt aggregation using coarse-grained molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Vila Verde, Ana; Frenkel, Daan

    2010-03-01

    Bile salts are necessary for fat digestion due to their unusual surfactant properties: they assemble into small, polydisperse micelles and easily form mixed micelles with poorly soluble amphiphiles. Understanding these properties requires molecular scale information about bile salt micelles, something challenging to obtain experimentally but amenable to computational modeling. To address this issue we build a coarse-grained model of bile salts. We investigate their aggregation behavior through molecular dynamics simulations in a grand-canonical parallel tempering scheme. We validate our model against available solubility and light scattering data. Our results indicate that at physiological bile salt and counter ion concentrations, bile salts pack in many different orientations in pure bile micelles, contrary to standard surfactants. This feature may be physiologically relevant, allowing bile salts to solubilize the heterogeneous blends of fats typical of digestion.

  10. Implication of sortase-dependent proteins of Streptococcus thermophilus in adhesion to human intestinal epithelial cell lines and bile salt tolerance.

    PubMed

    Kebouchi, Mounira; Galia, Wessam; Genay, Magali; Soligot, Claire; Lecomte, Xavier; Awussi, Ahoefa Ablavi; Perrin, Clarisse; Roux, Emeline; Dary-Mourot, Annie; Le Roux, Yves

    2016-04-01

    Streptococcus thermophilus (ST) is a lactic acid bacterium widely used in dairy industry and displays several properties which could be beneficial for host. The objective of this study was to investigate, in vitro, the implication of sortase A (SrtA) and sortase-dependent proteins (SDPs) in the adhesion of ST LMD-9 strain to intestinal epithelial cells (IECs) and resistance to bile salt mixture (BSM; taurocholoate, deoxycholate, and cholate). The effect of mutations in prtS (protease), mucBP (MUCin-Binding Protein), and srtA genes in ST LMD-9 in these mechanisms were examined. The HT29-MTX, HT29-CL.16E, and Caco-2 TC7 cell lines were used. HT29-MTX and HT29-CL.16E cells express different mucins found in the gastro intestinal tract; whereas, Caco-2 TC7 express cell surface proteins found in the small intestine. All mutants showed different adhesion profiles depending on cell lines. The mutation in genes srtA and mucBP leads to a significant decrease in LMD-9 adhesion capacity to Caco-2 TC7 cells. A mutation in mucBP gene has also shown a significant decrease in LMD-9 adhesion capacity to HT29-CL.16E cells. However, no difference was observed using HT29-MTX cells. Furthermore, ST LMD-9 and srtA mutant were resistant to BSM up to 3 mM. Contrariwise, no viable bacteria were detected for prtS and mucBP mutants at this concentration. Two conclusions could be drawn. First, SDPs could be involved in the LMD-9 adhesion depending on the cell lines indicating the importance of eukaryotic-cell surface components in adherence. Second, SDPs could contribute to resistance to bile salts probably by maintaining the cell membrane integrity. PMID:26820650

  11. Effects of essential fatty acid deficiency on enterohepatic circulation of bile salts in mice.

    PubMed

    Lukovac, S; Los, E L; Stellaard, F; Rings, E H H M; Verkade, H J

    2009-09-01

    Essential fatty acid (EFA) deficiency in mice has been associated with increased bile production, which is mainly determined by the enterohepatic circulation (EHC) of bile salts. To establish the mechanism underlying the increased bile production, we characterized in detail the EHC of bile salts in EFA-deficient mice using stable isotope technique, without interrupting the normal EHC. Farnesoid X receptor (FXR) has been proposed as an important regulator of bile salt synthesis and homeostasis. In Fxr(-/-) mice we additionally investigated to what extent alterations in bile production during EFA deficiency were FXR dependent. Furthermore, we tested in differentiating Caco-2 cells the effects of EFA deficiency on expression of FXR-target genes relevant for feedback regulation of bile salt synthesis. EFA deficiency-enhanced bile flow and biliary bile salt secretion were associated with elevated bile salt pool size and synthesis rate (+146 and +42%, respectively, P < 0.05), despite increased ileal bile salt reabsorption (+228%, P < 0.05). Cyp7a1 mRNA expression was unaffected in EFA-deficient mice. However, ileal mRNA expression of Fgf15 (inhibitor of bile salt synthesis) was significantly reduced, in agreement with absent inhibition of the hepatic bile salt synthesis. Bile flow and biliary secretion were enhanced to the same extent in EFA-deficient wild-type and Fxr(-/-) mice, indicating contribution of other factors besides FXR in regulation of EHC during EFA deficiency. In vitro experiments show reduced induction of mRNA expression of relevant genes upon chenodeoxycholic acid and a selective FXR agonist GW4064 stimulation in EFA-deficient Caco-2 cells. In conclusion, our data indicate that EFA deficiency is associated with interrupted negative feedback of bile salt synthesis, possibly because of reduced ileal Fgf15 expression.

  12. Exon-skipping and mRNA decay in human liver tissue: molecular consequences of pathogenic bile salt export pump mutations

    PubMed Central

    Dröge, Carola; Schaal, Heiner; Engelmann, Guido; Wenning, Daniel; Häussinger, Dieter; Kubitz, Ralf

    2016-01-01

    The bile salt export pump BSEP mediates bile formation. Over 150 BSEP mutations are associated with progressive familial intrahepatic cholestasis type 2 (PFIC-2), with few characterised specifically. We examined liver tissues from two PFIC-2 patients compound heterozygous for the splice-site mutation c.150 + 3A > C and either c.2783_2787dup5 resulting in a frameshift with a premature termination codon (child 1) or p.R832C (child 2). Splicing was analysed with a minigene system and mRNA sequencing from patients’ livers. Protein expression was shown by immunofluorescence. Using the minigene, c.150 + 3A > C causes complete skipping of exon 3. In liver tissue of child 1, c.2783_2787dup5 was found on DNA but not on mRNA level, implying nonsense-mediated mRNA decay (NMD) when c.2783_2787dup5 is present. Still, BSEP protein as well as mRNA with and without exon 3 were detectable and can be assigned to the c.150 + 3A > C allele. Correctly spliced transcripts despite c.150 + 3A > C were also confirmed in liver of child 2. In conclusion, we provide evidence (1) for effective NMD due to a BSEP frameshift mutation and (2) partial exon-skipping due to c.150 + 3A > C. The results illustrate that the extent of exon-skipping depends on the genomic and cellular context and that regulation of splicing may have therapeutic potential. PMID:27114171

  13. Differential proteomic analysis of outer membrane enriched extracts of Bacteroides fragilis grown under bile salts stress.

    PubMed

    Boente, Renata F; Pauer, Heidi; Silva, Deborah N S; Filho, Joaquim Santos; Sandim, Vanessa; Antunes, Luis Caetano M; Ferreira, Rosana Barreto Rocha; Zingali, Russolina B; Domingues, Regina M C P; Lobo, Leandro A

    2016-06-01

    Bacteroides fragilis is the most commonly isolated anaerobic bacteria from infectious processes. Several virulence traits contribute to the pathogenic nature of this bacterium, including the ability to tolerate the high concentrations of bile found in the gastrointestinal tract (GIT). The activity of bile salts is similar to detergents and may lead to membrane permeabilization and cell death. Modulation of outer membrane proteins (OMPs) is considered a crucial event to bile salts resistance. The primary objective of the current work was to identify B. fragilis proteins associated with the stress induced by high concentration of bile salts. The outer membrane of B. fragilis strain 638R was isolated after growth either in the presence of 2% conjugated bile salts or without bile salts. The membrane fractions were separated on SDS-PAGE and analyzed by ESI-Q/TOF tandem mass spectrometry. A total of 37 proteins were identified; among them nine were found to be expressed exclusively in the absence of bile salts whereas eight proteins were expressed only in the presence of bile salts. These proteins are related to cellular functions such as transport through membrane, nutrient uptake, and protein-protein interactions. This study demonstrates the alteration of OMPs composition in B. fragilis during bile salts stress resistance and adaptation to environmental changes. Proteomics of OMPs was also shown to be a useful approach in the identification of new targets for functional analyses.

  14. Lithocholic acid decreases expression of bile salt export pump through farnesoid X receptor antagonist activity.

    PubMed

    Yu, Jinghua; Lo, Jane-L; Huang, Li; Zhao, Annie; Metzger, Edward; Adams, Alan; Meinke, Peter T; Wright, Samuel D; Cui, Jisong

    2002-08-30

    Bile salt export pump (BSEP) is a major bile acid transporter in the liver. Mutations in BSEP result in progressive intrahepatic cholestasis, a severe liver disease that impairs bile flow and causes irreversible liver damage. BSEP is a target for inhibition and down-regulation by drugs and abnormal bile salt metabolites, and such inhibition and down-regulation may result in bile acid retention and intrahepatic cholestasis. In this study, we quantitatively analyzed the regulation of BSEP expression by FXR ligands in primary human hepatocytes and HepG2 cells. We demonstrate that BSEP expression is dramatically regulated by ligands of the nuclear receptor farnesoid X receptor (FXR). Both the endogenous FXR agonist chenodeoxycholate (CDCA) and synthetic FXR ligand GW4064 effectively increased BSEP mRNA in both cell types. This up-regulation was readily detectable at as early as 3 h, and the ligand potency for BSEP regulation correlates with the intrinsic activity on FXR. These results suggest BSEP as a direct target of FXR and support the recent report that the BSEP promoter is transactivated by FXR. In contrast to CDCA and GW4064, lithocholate (LCA), a hydrophobic bile acid and a potent inducer of cholestasis, strongly decreased BSEP expression. Previous studies did not identify LCA as an FXR antagonist ligand in cells, but we show here that LCA is an FXR antagonist with partial agonist activity in cells. In an in vitro co-activator association assay, LCA decreased CDCA- and GW4064-induced FXR activation with an IC(50) of 1 microm. In HepG2 cells, LCA also effectively antagonized GW4064-enhanced FXR transactivation. These data suggest that the toxic and cholestatic effect of LCA in animals may result from its down-regulation of BSEP through FXR. Taken together, these observations indicate that FXR plays an important role in BSEP gene expression and that FXR ligands may be potential therapeutic drugs for intrahepatic cholestasis.

  15. Clinical application of transcriptional activators of bile salt transporters☆

    PubMed Central

    Baghdasaryan, Anna; Chiba, Peter; Trauner, Michael

    2014-01-01

    Hepatobiliary bile salt (BS) transporters are critical determinants of BS homeostasis controlling intracellular concentrations of BSs and their enterohepatic circulation. Genetic or acquired dysfunction of specific transport systems causes intrahepatic and systemic retention of potentially cytotoxic BSs, which, in high concentrations, may disturb integrity of cell membranes and subcellular organelles resulting in cell death, inflammation and fibrosis. Transcriptional regulation of canalicular BS efflux through bile salt export pump (BSEP), basolateral elimination through organic solute transporters alpha and beta (OSTα/OSTβ) as well as inhibition of hepatocellular BS uptake through basolateral Na+-taurocholate cotransporting polypeptide (NTCP) represent critical steps in protection from hepatocellular BS overload and can be targeted therapeutically. In this article, we review the potential clinical implications of the major BS transporters BSEP, OSTα/OSTβ and NTCP in the pathogenesis of hereditary and acquired cholestatic syndromes, provide an overview on transcriptional control of these transporters by the key regulatory nuclear receptors and discuss the potential therapeutic role of novel transcriptional activators of BS transporters in cholestasis. PMID:24333169

  16. Simple steatosis sensitizes cholestatic rats to liver injury and dysregulates bile salt synthesis and transport

    PubMed Central

    Lionarons, Daniël A.; Heger, Michal; van Golen, Rowan F.; Alles, Lindy K.; van der Mark, Vincent A.; Kloek, Jaap J.; de Waart, Dirk R.; Marsman, Hendrik A.; Rusch, Henny; Verheij, Joanne; Beuers, Ulrich; Paulusma, Coen C.; van Gulik, Thomas M.

    2016-01-01

    Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder. It is uncertain if simple steatosis, the initial and prevailing form of NAFLD, sensitizes the liver to cholestasis. Here, we compared the effects of obstructive cholestasis in rats with a normal liver versus rats with simple steatosis induced by a methionine/choline-deficient diet. We found that plasma liver enzymes were higher and hepatic neutrophil influx, inflammation, and fibrosis were more pronounced in animals with combined steatosis and cholestasis compared to cholestasis alone. Circulating bile salt levels were markedly increased and hepatic bile salt composition shifted from hydrophilic tauro-β-muricholate to hydrophobic taurocholate. This shift was cytotoxic for HepG2 hepatoma cells. Gene expression analysis revealed induction of the rate-limiting enzyme in bile salt synthesis, cytochrome P450 7a1 (CYP7A1), and modulation of the hepatic bile salt transport system. In conclusion, simple steatosis sensitizes the liver to cholestatic injury, inflammation, and fibrosis in part due to a cytotoxic shift in bile salt composition. Plasma bile salt levels were elevated, linked to dysregulation of bile salt synthesis and enhanced trafficking of bile salts from the liver to the systemic circulation. PMID:27535001

  17. Comparative studies of bile salts. A new type of bile salt from Arapaima gigas (Cuvier) (family Osteoglossidae)

    PubMed Central

    Haslewood, G. A. D.; Tökés, L.

    1972-01-01

    1. Arapaima gigas bile salts were hydrolysed by alkali or cleaved with dioxan–trichloroacetic acid to give cholic acid, arapaimic acid, arapaimol-A and arapaimol-B. 2. I.r., n.m.r. and mass spectroscopy and [α]D measurements indicated that arapaimic acid and arapaimol-A and -B are respectively 2α,3α,7α,12α-tetrahydroxy-5β,25∈-cholestan-26-oic acid, 5β,25R-cholestane-2β,3α,7α,12α,26-pentol and 5β-cholestane-2β,3α,7α,12α,26,27-hexol. 3. Partial synthesis of 2β,3α,7α,12α-tetrahydroxy-5α- and -5β-cholan-24-oic acid and their spectral examination fully confirmed these conclusions. 4. A. gigas bile salts show primitive features in that they comprise alcohol sulphates and a C27 acid; they are also specialized in showing 2β-hydroxylation. PMID:5073728

  18. Proteomic Analysis of Global Changes in Protein Expression during Bile Salt Exposure of Bifidobacterium longum NCIMB 8809

    PubMed Central

    Sánchez, Borja; Champomier-Vergès, Marie-Christine; Anglade, Patricia; Baraige, Fabienne; de los Reyes-Gavilán, Clara G.; Margolles, Abelardo; Zagorec, Monique

    2005-01-01

    Adaptation to and tolerance of bile stress are among the main limiting factors to ensure survival of bifidobacteria in the intestinal environment of humans. The effect of bile salts on protein expression patterns of Bifidobacterium longum was examined. Protein pattern comparison of strains grown with or without bile extract allowed us to identify 34 different proteins whose expression was regulated. The majority of these proteins were induced after both a minor (0.6 g liter−1) and a major (1.2 g liter−1) exposure to bile. These include general stress response chaperones, proteins involved in transcription and translation and in the metabolism of amino acids and nucleotides, and several enzymes of glycolysis and pyruvate catabolism. Remarkably, xylulose 5-phosphate/fructose 6-phosphate phosphoketolase, the key enzyme of the so-called bifidobacterial shunt, was found to be upregulated, and the activity on fructose 6-phosphate was significantly higher for protein extracts of cells grown in the presence of bile. Changes in the levels of metabolic end products (acetate and lactate) were also detected. These results suggest that bile salts, to which bifidobacteria are naturally exposed, induce a complex physiological response rather than a single event in which proteins from many different functional categories take part. This study has extended our understanding of the molecular mechanism underlying the capacity of intestinal bifidobacteria to tolerate bile. PMID:16077128

  19. Effects of bile salts on percolation and size of AOT reversed micelles.

    PubMed

    Yang, Hui; Erford, Karen; Kiserow, Douglas J; McGown, Linda B

    2003-06-15

    The effects of two trihydroxy bile salts, sodium taurocholate (NaTC) and 3-[(3-cholamidylpropyl)dimethylammonio]-1-propane sulfonate (CHAPS), on the size, shape and percolation temperature of reversed micelles formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in isooctane were studied. The percolation temperature of the reversed micelles decreased upon inclusion of bile salts, indicating increased water uptake. Dynamic light scattering (DLS) measurements showed consistent enlargement of reversed micelles upon addition of the bile salts; the hydrodynamic radius increased sixfold in the presence of 10 mM CHAPS and doubled in the presence of 5 mM NaTC. Inclusion of the enzyme yeast alcohol dehydrogenase (YADH) increased the percolation temperature and distorted the spherical structure of the AOT reversed micelles. The spherical structure was restored upon addition of bile salt. These results may help to explain the increase in activity of YADH in AOT reversed micelles upon addition of bile salts.

  20. Activation of CFTR by ASBT-mediated bile salt absorption.

    PubMed

    Bijvelds, Marcel J C; Jorna, Huub; Verkade, Henkjan J; Bot, Alice G M; Hofmann, Franz; Agellon, Luis B; Sinaasappel, Maarten; de Jonge, Hugo R

    2005-11-01

    In cholangiocytes, bile salt (BS) uptake via the apical sodium-dependent bile acid transporter (ASBT) may evoke ductular flow by enhancing cAMP-mediated signaling to the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. We considered that ASBT-mediated BS uptake in the distal ileum might also modulate intestinal fluid secretion. Taurocholate (TC) induced a biphasic rise in the short circuit current across ileal tissue, reflecting transepithelial electrogenic ion transport. This response was sensitive to bumetanide and largely abrogated in Cftr-null mice, indicating that it predominantly reflects CFTR-mediated Cl- secretion. The residual response in Cftr-null mice could be attributed to electrogenic ASBT activity, as it matched the TC-coupled absorptive Na+ flux. TC-evoked Cl- secretion required ASBT-mediated TC uptake, because it was blocked by a selective ASBT inhibitor and was restricted to the distal ileum. Suppression of neurotransmitter or prostaglandin release, blocking of the histamine H1 receptor, or pretreatment with 5-hydroxytryptamine did not abrogate the TC response, suggesting that neurocrine or immune mediators of Cl- secretion are not involved. Responses to TC were retained after carbachol treatment and after permeabilization of the basolateral membrane with nystatin, indicating that BS modulate CFTR channel gating rather than the driving force for Cl- exit. TC-induced Cl- secretion was maintained in cGMP-dependent protein kinase II-deficient mice and only partially inhibited by the cAMP-dependent protein kinase inhibitor H89, suggesting a mechanism of CFTR activation different from cAMP or cGMP signaling. We conclude that active BS absorption in the ileum triggers CFTR activation and, consequently, local salt and water secretion, which may serve to prevent intestinal obstruction in the postprandial state. PMID:16037545

  1. Bile acid salt binding with colesevelam HCl is not affected by suspension in common beverages.

    PubMed

    Hanus, Martin; Zhorov, Eugene

    2006-12-01

    It has been previously reported that anions in common beverages may bind to bile acid sequestrants (BAS), reducing their capacity for binding bile acid salts. This study examined the ability of the novel BAS colesevelam hydrochloride (HCl), in vitro, to bind bile acid sodium salts following suspension in common beverages. Equilibrium binding was evaluated under conditions of constant time and varying concentrations of bile acid salts in simulated intestinal fluid (SIF). A stock solution of sodium salts of glycochenodeoxycholic acid (GCDC), taurodeoxycholic acid (TDC), and glycocholic acid (GC), was added to each prepared sample of colesevelam HCl. Bile acid salt binding was calculated by high-performance liquid chromatography (HPLC) analysis. Kinetics experiments were conducted using constant initial bile acid salt concentrations and varying binding times. The affinity, capacity, and kinetics of colesevelam HCl binding for GCDC, TDC, and GC were not significantly altered after suspension in water, carbonated water, Coca-Cola, Sprite, grape juice, orange juice, tomato juice, or Gatorade. The amount of bile acid sodium salt bound as a function of time was unchanged by pretreatment with any beverage tested. The in vitro binding characteristics of colesevelam HCl are unchanged by suspension in common beverages. PMID:16937334

  2. Biosynthesis and Trafficking of the Bile Salt Export Pump, BSEP: Therapeutic Implications of BSEP Mutations

    PubMed Central

    Soroka, Carol J.; Boyer, James L.

    2013-01-01

    The bile salt export pump (BSEP, ABCB11) is the primary transporter of bile acids from the hepatocyte to the biliary system. This rate-limiting step in bile formation is essential to the formation of bile salt dependent bile flow, the enterohepatic circulation of bile acids, and the digestion of dietary fats. Mutations in BSEP are associated with cholestatic diseases such as progressive familial intrahepatic cholestasis type 2 (PFIC2), benign recurrent intrahepatic cholestasis type 2 (BRIC2), drug-induced cholestasis, and intrahepatic cholestasis of pregnancy. Development of clinical therapies for these conditions necessitates a clear understanding of the cell biology of biosynthesis, trafficking, and transcriptional and translational regulation of BSEP. This chapter will focus on the molecular and cell biological aspects of this critical hepatic membrane transporter. PMID:23685087

  3. Bile salt surfactants in micellar electrokinetic capillary chromatography: Application to hydrophobic molecule separations

    SciTech Connect

    Cole, R.O.; Sepaniak, M.J. . Dept. of Chemistry); Hinze, W.L. . Dept. of Chemistry); Gorse, J.; Oldiges, K. . Dept. of Chemistry)

    1990-01-01

    Bile Salt surfactants are used in the micellar electrokinetic capillary chromatography (MECC) separation of various hydrophobic compounds. The use of methanol in the mobile phase allows the separation of previously intractable compounds including polyaromatic hydrocarbons. The effects of methanol on critical micelle concentration is investigated for sodium dodecyl sulfate (SDS) and the bile salt sodium cholate. It is determined that the unique structure of the bile salt micelle is much more tolerant to the addition of organic solvents than SDS, thereby increasing the scope of applications of MECC to include hydrophobic compounds. 30 refs., 9 figs.

  4. Clinical value of bile salt tests in anicteric liver disease.

    PubMed Central

    Douglas, J G; Beckett, G J; Nimmo, I A; Finlayson, N D; Percy-Robb, I W

    1981-01-01

    Fasting and postprandial serum bile salt concentrations and intravenous glycocholate disappearance were studied in 20 patients with anicteric liver disease who had only minor abnormalities of conventional liver function tests. Abnormalities in the fasting or two hour postprandial conjugated cholate concentrations were found in all but one of the patients who had an abnormality in bilirubin concentration. In these patients, fasting and postprandial conjugated cholate concentrations were raised on average three and two times respectively above the upper limit of the reference range, while bilirubin concentration was raised only 50%. Postprandial conjugated cholate concentrations were also abnormal in two patients with normal bilirubin concentrations. Measurement of fasting and postprandial conjugated chenodeoxycholate concentration and intravenous glycocholate disappearance proved less informative than the fasting and postprandial conjugated cholate test. These results suggest that, where bilirubin concentrations are normal or only slightly raised, measurement of serum fasting and two hour postprandial conjugated cholate concentrations may prove helpful in the detection of minor abnormalities in hepatic anion transport. PMID:7215945

  5. Mixtures of lecithin and bile salt can form highly viscous wormlike micellar solutions in water.

    PubMed

    Cheng, Chih-Yang; Oh, Hyuntaek; Wang, Ting-Yu; Raghavan, Srinivasa R; Tung, Shih-Huang

    2014-09-01

    The self-assembly of biological surfactants in water is an important topic for study because of its relevance to physiological processes. Two common types of biosurfactants are lecithin (phosphatidylcholine) and bile salts, which are both present in bile and involved in digestion. Previous studies on lecithin-bile salt mixtures have reported the formation of short, rodlike micelles. Here, we show that lecithin-bile salt micelles can be further induced to grow into long, flexible wormlike structures. The formation of long worms and their resultant entanglement into transient networks is reflected in the rheology: the fluids become viscoelastic and exhibit Maxwellian behavior, and their zero-shear viscosity can be up to a 1000-fold higher than that of water. The presence of worms is further confirmed by data from small-angle neutron and X-ray scattering and from cryo-transmission electron microscopy (cryo-TEM). We find that micellar growth peaks at a specific molar ratio (near equimolar) of bile salt:lecithin, which suggests a strong binding interaction between the two species. In addition, micellar growth also requires a sufficient concentration of background electrolyte such as NaCl or sodium citrate that serves to screen the electrostatic repulsion of the amphiphiles and to "salt out" the amphiphiles. We postulate a mechanism based on changes in the molecular geometry caused by bile salts and electrolytes to explain the micellar growth.

  6. NMR characterization of the interaction of the Salmonella type III secretion system protein SipD and bile salts.

    PubMed

    Wang, Yu; Nordhues, Bryce A; Zhong, Dalian; De Guzman, Roberto N

    2010-05-18

    Salmonella and Shigella bacteria require the type III secretion system (T3SS) to inject virulence proteins into their hosts and initiate infections. The tip proteins SipD and IpaD are critical components of the Salmonella and Shigella T3SS, respectively. Recently, SipD and IpaD have been shown to interact with bile salts, which are enriched in the intestines, and are hypothesized to act as environmental sensors for these enteric pathogens. Bile salts activate the Shigella T3SS but repress the Salmonella T3SS, and the mechanism of this differing response to bile salts is poorly understood. Further, how SipD binds to bile salts is currently unknown. Computer modeling predicted that IpaD binds the bile salt deoxycholate in a cleft formed by the N-terminal domain and the long central coiled coil of IpaD. Here, we used NMR methods to determine which SipD residues are affected by the interaction with the bile salts deoxycholate, chenodeoxycholate, and taurodeoxcholate. The bile salts perturbed nearly the same set of SipD residues; however, the largest chemical shift perturbations occurred away from what was predicted for the bile salt binding site in IpaD. Our NMR results indicate that that bile salt interaction of SipD will be different from what was predicted for IpaD, suggesting a possible mechanism for the differing response of Salmonella and Shigella to bile salts.

  7. Changes in bile acids, FGF-19 and sterol absorption in response to bile salt hydrolase active L. reuteri NCIMB 30242.

    PubMed

    Martoni, Christopher J; Labbé, Alain; Ganopolsky, Jorge G; Prakash, Satya; Jones, Mitchell L

    2015-01-01

    The size and composition of the circulating bile acid (BA) pool are important factors in regulating the human gut microbiota. Disrupted regulation of BA metabolism is implicated in several chronic diseases. Bile salt hydrolase (BSH)-active Lactobacillus reuteri NCIMB 30242, previously shown to decrease LDL-cholesterol and increase circulating BA, was investigated for its dose response effect on BA profile in a pilot clinical study. Ten otherwise healthy hypercholesterolemic adults, recruited from a clinical trial site in London, ON, were randomized to consume delayed release or standard release capsules containing L. reuteri NCIMB 30242 in escalating dose over 4 weeks. In another aspect, 4 healthy normocholesterolemic subjects with LDL-C below 3.4 mmol/l received delayed release L. reuteri NCIMB 30242 at a constant dose over 4 weeks. The primary outcome measure was the change in plasma BA profile over the intervention period. Additional outcomes included circulating fibroblast growth factor (FGF)-19, plant sterols and LDL-cholesterol as well as fecal microbiota and bsh gene presence. After one week of intervention subjects receiving delayed release L. reuteri NCIMB 30242 increased total BA by 1.13 ± 0.67 μmol/l (P = 0.02), conjugated BA by 0.67 ± 0.39 μmol/l (P = 0.02) and unconjugated BA by 0.46 ± 0.43 μmol/l (P = 0.07), which represented a greater than 2-fold change relative to baseline. Increases in BA were largely maintained post-week 1 and were generally correlated with FGF-19 and inversely correlated with plant sterols. This is the first clinical support showing that a BSH-active probiotic can significantly and rapidly influence BA metabolism and may prove useful in chronic diseases beyond hypercholesterolemia. PMID:25612224

  8. Exocrine pancreatic secretion and plasma levels of cholecystokinin, pancreatic polypeptide, and somatostatin after single and combined intraduodenal application of different bile salts in man.

    PubMed

    Riepl, R L; Fiedler, F; Kowalski, C; Teufel, J; Lehnert, P

    1996-01-01

    Bile salts are intraduodenal stimulants of basal pancreatic secretion. This study aims to show whether the three main bile salts of human bile differ in their action on pancreatic secretion, and whether they enhance or inhibit each other after combined use. Furthermore, the effect on gastroenteropancreatic peptide release is evaluated. Twelve subjects were provided with a gastroduodenal double-lumen tube. Equimolar doses (0.6 mmol) of taurocholate (322 mg), taurodeoxycholate (313 mg), and a combination of both stimuli were given intraduodenally. Another 12 subjects received taurochenodeoxycholate (313 mg) instead of taurocholate. Volume, bicarbonate, trypsin, and lipase were determined in duodenal aspirates. Cholecystokinin, pancreatic polypeptide, and somatostatin were measured radioimmunologically in plasma samples. All bile salts and combinations exerted a significant hydrokinetic and ecbolic effect. The hydrokinetic response of the combined stimuli was significantly higher as compared with taurocholate and taurochenodeoxycholate, respectively. As far as concerns the ecbolic response, the difference was significant only for trypsin output as compared with taurochenodeoxycholate. Plasma cholecystokinin rose significantly only after the combined stimuli. Pancreatic polypeptide and somatostatin increased significantly after all stimuli, except pancreatic polypeptide after taurocholate. Combined use enhances the hydrokinetic and ecbolic effects of single bile salts. Cholecystokinin may, hereby, be involved as a mediator of the ecbolic effect. Pancreatic polypeptide release indicates cholinergic mechanisms as further mediators. As demonstrated by somatostatin release, counter-regulatory mechanisms are also triggered by intraduodenal bile salts.

  9. Exocrine pancreatic secretion and plasma levels of cholecystokinin, pancreatic polypeptide, and somatostatin after single and combined intraduodenal application of different bile salts in man.

    PubMed

    Riepl, R L; Fiedler, F; Kowalski, C; Teufel, J; Lehnert, P

    1996-01-01

    Bile salts are intraduodenal stimulants of basal pancreatic secretion. This study aims to show whether the three main bile salts of human bile differ in their action on pancreatic secretion, and whether they enhance or inhibit each other after combined use. Furthermore, the effect on gastroenteropancreatic peptide release is evaluated. Twelve subjects were provided with a gastroduodenal double-lumen tube. Equimolar doses (0.6 mmol) of taurocholate (322 mg), taurodeoxycholate (313 mg), and a combination of both stimuli were given intraduodenally. Another 12 subjects received taurochenodeoxycholate (313 mg) instead of taurocholate. Volume, bicarbonate, trypsin, and lipase were determined in duodenal aspirates. Cholecystokinin, pancreatic polypeptide, and somatostatin were measured radioimmunologically in plasma samples. All bile salts and combinations exerted a significant hydrokinetic and ecbolic effect. The hydrokinetic response of the combined stimuli was significantly higher as compared with taurocholate and taurochenodeoxycholate, respectively. As far as concerns the ecbolic response, the difference was significant only for trypsin output as compared with taurochenodeoxycholate. Plasma cholecystokinin rose significantly only after the combined stimuli. Pancreatic polypeptide and somatostatin increased significantly after all stimuli, except pancreatic polypeptide after taurocholate. Combined use enhances the hydrokinetic and ecbolic effects of single bile salts. Cholecystokinin may, hereby, be involved as a mediator of the ecbolic effect. Pancreatic polypeptide release indicates cholinergic mechanisms as further mediators. As demonstrated by somatostatin release, counter-regulatory mechanisms are also triggered by intraduodenal bile salts. PMID:9032583

  10. Characterization and purification of bile salt hydrolase from Lactobacillus sp. strain 100-100

    SciTech Connect

    Lundeen, S.G.; Savage, D.C. )

    1990-08-01

    The authors have characterized and purified the bile salt hydrolase from Lactobacillus sp. strain 100-100. Bile salt hydrolase from cells of the strain was purified with column and high-performance liquid chromatography. The activity was assayed in whole cells and cell-free extracts with either a radiochemical assay involving ({sup 14}C)taurocholic acid or a nonradioactive assay involving trinitrobenzene sulfonate. The activity was detectable only in stationary-phase cells. Within 20 min after conjugated bile acids were added to stationary-phase cultures of strain 100-100, the activity in whole cells increased to levels three- to fivefold higher than in cells from cultures grown in medium free of bile salts. In cell-free extracts, however, the activity was about equal whether or not the cells have been grown with bile salts present. When supernatant solutions from cultures grown in medium containing taurocholic acid were used to suspend cells grown in medium free of the bile salt, the bile salt hydrolase activity detected in whole cells increased two- to threefold. Two forms of the hydrolase were purified from the cells and designated hydrolases A and B. They eluted from anion-exchange high-performance liquid chromatography in two sets of fractions, A at 0.15 M NaCl and B at 0.18 M NaCl. Their apparent molecular weights in nondenaturing polyacrylamide gel electrophoresis were 115,000 and 105,000, respectively. However, discrepancies existed in the apparent molecular weights and number of peptides detected in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the two forms. Whether the enzyme exists in two forms in the cells remains to be determined.

  11. Bile salts induce expression of the afimbrial LDA adhesin of atypical enteropathogenic Escherichia coli.

    PubMed

    Torres, Alfredo G; Tutt, Christopher B; Duval, Lisabeth; Popov, Vsevolod; Nasr, Abdelhakim Ben; Michalski, Jane; Scaletsky, Isabel C A

    2007-04-01

    Atypical enteropathogenic Escherichia coli (aEPEC) strains are frequently implicated in infant diarrhoea in developing countries. Not much is known about the adherence properties of aEPEC; however, it has been shown that these strains can adhere to tissue-cultured cells. A chromosomal region designated the locus for diffuse adherence (LDA) confers aEPEC strain 22 the ability to adhere to culture cells. LDA is an afimbrial adhesin that contains a major subunit, LdaG, whose expression is induced on MacConkey agar at 37 degrees C. We hypothesized that the bile salts found in this culture media induce the expression of LdaG. Strain 22 and the LdaG mutant were grown in Luria-Bertani (LB) media in the presence or absence of bile salts and heat-extracted surface-expressed proteins were separated by SDS-PAGE to determine whether expression of the 25 kDa LdaG protein was induced. Western blot analysis with anti-LdaG confirmed that bile salts enhance LdaG expression at 37 degrees C. Adhesion assays on HeLa cells revealed that adhesion in a diffuse pattern of strain 22 increased in the presence of bile salts. We also confirmed that expression of the localized adherence pattern observed in the ldaG mutant required the presence of a large cryptic plasmid found in strain 22 and that this phenotype was not induced by bile salts. At the transcriptional level, the ldaG-lacZ promoter fusion displayed maximum beta-galactosidase activity when the parent strain was grown in LB supplemented with bile salts. Fluorescence Activated Cell Sorting analysis, immunogold labelling electron microscopy and immunofluorescence using anti-LdaG sera confirmed that LDA is a bile salts-inducible surface-expressed afimbrial adhesin. Finally, LdaG expression was induced in presence of individual bile salts but not by other detergents. We concluded that bile salts increase expression of LDA, conferring a diffuse adherence pattern and having an impact on the adhesion properties of this aEPEC strain.

  12. Bile salts affect expression of Escherichia coli O157:H7 genes for virulence and iron acquisition, and promote growth under iron limiting conditions.

    PubMed

    Hamner, Steve; McInnerney, Kate; Williamson, Kerry; Franklin, Michael J; Ford, Timothy E

    2013-01-01

    Bile salts exhibit potent antibacterial properties, acting as detergents to disrupt cell membranes and as DNA-damaging agents. Although bacteria inhabiting the intestinal tract are able to resist bile's antimicrobial effects, relatively little is known about how bile influences virulence of enteric pathogens. Escherichia coli O157:H7 is an important pathogen of humans, capable of causing severe diarrhea and more serious sequelae. In this study, the transcriptome response of E. coli O157:H7 to bile was determined. Bile exposure induced significant changes in mRNA levels of genes related to virulence potential, including a reduction of mRNA for the 41 genes making up the locus of enterocyte effacement (LEE) pathogenicity island. Bile treatment had an unusual effect on mRNA levels for the entire flagella-chemotaxis regulon, resulting in two- to four-fold increases in mRNA levels for genes associated with the flagella hook-basal body structure, but a two-fold decrease for "late" flagella genes associated with the flagella filament, stator motor, and chemotaxis. Bile salts also caused increased mRNA levels for seventeen genes associated with iron scavenging and metabolism, and counteracted the inhibitory effect of the iron chelating agent 2,2'-dipyridyl on growth of E. coli O157:H7. These findings suggest that E. coli O157:H7 may use bile as an environmental signal to adapt to changing conditions associated with the small intestine, including adaptation to an iron-scarce environment.

  13. Investigations of novel unsaturated bile salts of male sea lamprey as potential chemical cues

    USGS Publications Warehouse

    Johnson, Nicholas S.; Yun, Sang-Seon; Li, Weiming

    2014-01-01

    Sulfated bile salts function as chemical cues that coordinate reproduction in sea lamprey, Petromyzon marinus. 7α, 12α, 24-trihydroxy-5α-cholan-3-one 24-sulfate (3kPZS) is the most abundant known bile salt released by sexually mature male sea lampreys and attracts ovulated females. However, previous studies showed that the male-produced pheromone consists of unidentified components in addition to 3kPZS. Here, analysis of water conditioned with mature male sea lampreys indicated the presence of 4 oxidized, unsaturated compounds with molecular weights of 466 Da, 468 Da, and 2 of 470 Da. These compounds were not detectable in water conditioned with immature male sea lampreys. By using mass spectrometry, 4 A-ring unsaturated sulfated bile salts were tentatively identified from male washings as 2 4-ene, a 1-ene, and a 1,4-diene analogs. These were synthesized to determine if they attracted ovulated female sea lampreys to spawning nests in natural streams. One of the novel synthetic bile salts, 3 keto-1-ene PZS, attracted ovulated females to the point of application at a concentration of 10-12 M. This study reveals the structural diversity of bile salts in sea lamprey, some of which have been demonstrated to be pheromonal cues.

  14. Investigations of novel unsaturated bile salts of male sea lamprey as potential chemical cues.

    PubMed

    Johnson, Nicholas S; Yun, Sang-Seon; Li, Weiming

    2014-10-01

    Sulfated bile salts function as chemical cues that coordinate reproduction in sea lamprey, Petromyzon marinus. 7α, 12α, 24-trihydroxy-5α-cholan-3-one 24-sulfate (3kPZS) is the most abundant known bile salt released by sexually mature male sea lampreys and attracts ovulated females. However, previous studies showed that the male-produced pheromone consists of unidentified components in addition to 3kPZS. Here, analysis of water conditioned with mature male sea lampreys indicated the presence of 4 oxidized, unsaturated compounds with molecular weights of 466 Da, 468 Da, and 2 of 470 Da. These compounds were not detectable in water conditioned with immature male sea lampreys. By using mass spectrometry, 4 A-ring unsaturated sulfated bile salts were tentatively identified from male washings as 2 4-ene, a 1-ene, and a 1,4-diene analogs. These were synthesized to determine if they attracted ovulated female sea lampreys to spawning nests in natural streams. One of the novel synthetic bile salts, 3 keto-1-ene PZS, attracted ovulated females to the point of application at a concentration of 10(-12) M. This study reveals the structural diversity of bile salts in sea lamprey, some of which have been demonstrated to be pheromonal cues.

  15. Biliary albumin excretion induced by bile salts in rats is a pathological phenomenon

    SciTech Connect

    Ohta, M.; Kitani, K.; Kanai, S. )

    1989-09-01

    The bile to plasma 125I-albumin concentration ratio (B/P ratio) was examined before and during various bile salt infusions in male Wistar rats that had previously received iv injection of 125I-albumin. Endogenous rat albumin and IgG concentrations in the bile were also determined by a single radial immunodiffusion method. Taurocholate (TC) infusion (1.0 mumol/min/100 g body wt) significantly increased the bile flow rate in the first hr but the flow began to decline in the second hr. The B/P ratio as well as rat albumin (and IgG) excretion into the bile significantly increased as early as 15 min after the start of TC infusion, and the increase became more pronounced in the second hr, when the bile flow began to decrease. Infusion of taurochenodeoxycholate (TCDC, 0.4 mumol/min/100 g) caused a reduction in bile flow 15 min after the start of infusion but the B/P ratio increased 40 times at its peak compared with the basal value before the bile salt infusion. Simultaneous infusion of tauroursodeoxycholate (TUDC, 0.6 mumol/min/100 g) and TCDC not only abolished the cholestasis induced by TCDC but maintained stable choleresis as long as for 2 hr. During this choleretic period, the B/P ration never exceeded the basal value. The choleresis induced by either taurodehydrocholate (TDHC) or bucolome was not accompanied by enhanced albumin excretion. In rats given TDHC infusion, albumin excretion started to increase only after the bile flow began to decline following the initial choleretic period. The enhanced excretion of albumin induced by TC and TCDC is therefore suggested to be caused not by the choleresis per se but by a possible concomitant increase in the communication between sinusoids and bile canaliculi, which eventually leads to cholestasis.

  16. Solubility of calcium salts of unconjugated and conjugated natural bile acids.

    PubMed

    Gu, J J; Hofmann, A F; Ton-Nu, H T; Schteingart, C D; Mysels, K J

    1992-05-01

    The approximate solubility products of the calcium salts of ten unconjugated bile acids and several taurine conjugated bile acids were determined. The formation of micelles, gels, and/or precipitates in relation to Ca2+,Na+, and bile salt concentration was summarized by "phase maps." Because the ratio of Ca2+ to bile salt in the precipitates was ca. 1:2, and the activity of Ca2+ but not that of bile salt (BA-) could be measured, the ion product of aCa2+ [BA-]2 was calculated. The ion product (= Ksp) ranged over nine orders of magnitude and the solubility thus ranged over three orders of magnitude; its value depended on the number and orientation of the hydroxyl groups in the bile acid. Ion products (in units of 10(-9) mol/l)3 were as follows: cholic (3 alpha OH,7 alpha OH,12 alpha OH) 640; ursocholic (3 alpha OH,7 beta OH,12 alpha OH) 2300; hyocholic (3 alpha OH,6 alpha OH,7 alpha OH) 11; ursodeoxycholic (3 alpha OH,7 beta OH) 91; chenodeoxycholic (3 alpha OH,7 alpha OH) 10; deoxycholic (3 alpha OH,12 alpha OH) 1.5; 12-epideoxycholic (lagodeoxycholic, 3 alpha OH,12 beta OH) 2.2; hyodeoxycholic (3 alpha OH,6 alpha OH) 0.7; and lithocholic (3 alpha OH) 0.00005. The critical micellization temperature of the sodium salt of murideoxycholic acid (3 alpha OH,6 beta OH) was greater than 100 degrees C, and its Ca2+ salt was likely to be very insoluble. Taurine conjugates were much more soluble than their corresponding unconjugated derivatives: chenodeoxycholyltaurine, 384; deoxycholyltaurine, 117; and cholyltaurine, greater than 10,000. Calcium salts of unconjugated bile acids precipitated rapidly in contrast to those of glycine conjugates which were metastable for months. Thus, hepatic conjugation of bile acids with taurine or glycine not only enhances solubility at acidic pH, but also at Ca2+ ion concentrations present in bile and intestinal content.

  17. Direct Measurement of the Thermodynamics of Chiral Recognition in Bile Salt Micelles.

    PubMed

    Anderson, Shauna L; Rovnyak, David; Strein, Timothy G

    2016-04-01

    Isothermal titration calorimetry (ITC) is shown to be a sensitive reporter of bile salt micellization and chiral recognition. Detailed ITC characterization of bile micelle formation as well as the chiral recognition capabilities of sodium cholate (NaC), deoxycholate (NaDC), and taurodeoxycholate (NaTDC) micelle systems are reported. The ΔH(demic) of these bile salt micelle systems is directly observable and is strongly temperature-dependent, allowing also for the determination of ΔCp(demic). Using the pseudo-phase separation model, ΔG(demic) and TΔS(demic) were also calculated. Chirally selective guest-host binding of model racemic compounds 1,1'-bi-2-napthol (BN) and 1,1'-binaphthyl-2,2'-diylhydrogenphosphate (BNDHP) to bile salt micelles was then investigated. The S-isomer was shown to bind more tightly to the bile salt micelles in all cases. A model was developed that allows for the quantitative determination of the enthalpic difference in binding affinity that corresponds to chiral selectivity, which is on the order of 1 kJ mol(-1).

  18. Biosynthesis and release of pheromonal bile salts in mature male sea lamprey

    PubMed Central

    2013-01-01

    Background In vertebrates, bile salts are primarily synthesized in the liver and secreted into the intestine where they aid in absorption of dietary fats. Small amounts of bile salts that are not reabsorbed into enterohepatic circulation are excreted with waste. In sexually mature male sea lamprey (Petromyzon marinus L.) a bile salt is released in large amounts across gill epithelia into water where it functions as a pheromone. We postulate that the release of this pheromone is associated with a dramatic increase in its biosynthesis and transport to the gills upon sexual maturation. Results We show an 8000-fold increase in transcription of cyp7a1, a three-fold increase in transcription of cyp27a1, and a six-fold increase in transcription of cyp8b1 in the liver of mature male sea lamprey over immature male adults. LC–MS/MS data on tissue-specific distribution and release rates of bile salts from mature males show a high concentration of petromyzonol sulfate (PZS) in the liver and gills of mature males. 3-keto petromyzonol sulfate (3kPZS, known as a male sex pheromone) is the primary compound released from gills, suggesting a conversion of PZS to 3kPZS in the gill epithelium. The PZS to 3kPZS conversion is supported by greater expression of hsd3b7 in gill epithelium. High expression of sult2b1 and sult2a1 in gill epithelia of mature males, and tissue-specific expression of bile salt transporters such as bsep, slc10a1, and slc10a2, suggest additional sulfation and transport of bile salts that are dependent upon maturation state. Conclusions This report presents a rare example where specific genes associated with biosynthesis and release of a sexual pheromone are dramatically upregulated upon sexual maturation in a vertebrate. We provide a well characterized example of a complex mechanism of bile salt biosynthesis and excretion that has likely evolved for an additional function of bile salts as a mating pheromone. PMID:24188124

  19. The excretion of cefuroxime in human bile.

    PubMed

    Thomas, M H; Dash, C H; Burnand, K G; Woodyer, A B

    1981-04-01

    Cefuroxime is a broad spectrum cephalosporin antibiotic. An intravenous injection of cefuroxime 1.5 g was administered to 25 patients after induction of anaesthesia for cholecystectomy. Concentrations of antibiotic were measured and the mean levels in microgram/ml found to be: serum 120.5, common bile duct bile 42.8, gallbladder bile 5.4, gallbladder wall 39.2. The drug levels exceeded the minimum inhibitory concentrations for most organisms commonly encountered in the biliary tract. There was no difference in cefuroxime levels in bile from functioning or non-functioning gallbladders. It is suggested that the diffusion of antibiotic into and out of the inflamed gallbladder is similar to that in abscesses and in experimental tissue cages. No side effects, toxicity or wound infections occurred.

  20. Interaction of Biologically Active Flavins inside Bile Salt Aggregates: Molecular Level Investigation.

    PubMed

    Maity, Banibrata; Ahmed, Sayeed Ashique; Seth, Debabrata

    2016-09-22

    In this work we have studied the photophysics of biologically active flavin molecule lumichrome (LCM) in different bile-salt aggregates. With alteration of the functional groups of the bile salts, the photophysics of confined fluorophore is largely affected and shows difference in their spectral behavior. This study also reveals the selective prototropic species of LCM present in bile salt aggregates. In the presence of the bile salt aggregates, LCM molecule shows excitation and emission wavelength-dependent emission properties, indicating switch over of the structural change of different prototropic form of the LCM molecule. The observation of higher rotational relaxation time in NaDC aggregates compared to NaTC aggregates clearly reflects that NaDC aggregates are more rigid due to its greater hydrophobicity and large in size, which is capable to bind the guest molecule more into their nanoconfined medium. Moreover, due to less acidic nature, NaDC aggregates have more ability to accept hydrogen bond from the LCM molecule and show the selective formation of isoalloxazine N10 anion (A1 monoanionic form) of LCM. PMID:27557394

  1. Interaction between dietary bioactive peptides of short length and bile salts in submicellar or micellar state.

    PubMed

    Guerin, Justine; Kriznik, Alexandre; Ramalanjaona, Nick; Le Roux, Yves; Girardet, Jean-Michel

    2016-10-15

    Bile salts act as steroidal detergents in the gut, and could also interact with peptides and improve their bioavailability, although the mechanism is unclear. The occurrence of direct interaction between milk bioactive peptides, Ile-Asn-Tyr-Trp, Leu-Asp-Gln-Trp, and Leu-Gln-Lys-Trp, and different bile salts in the submicellar or micellar state was investigated by intrinsic fluorescence measurement and dynamic light scattering, above the critical micellar concentration, the latter being determined by isothermal titration calorimetry. The peptides form aggregates, spontaneously. In the presence of bile salts, some released peptide monomers were bound to the micellar surface. The lack of hydrogen bonding involving the C12OH group of the steroid skeleton, and the acidic function of some bile salts, might promote the interaction with the peptides, as could the lack of the C12OH group, rather than that of the C7OH group. At submicellar concentrations, sodium taurochenodeoxycholate and taurodeoxycholate readily interacted with the most hydrophobic peptide Ile-Asn-Tyr-Trp. PMID:27173542

  2. [Preparation and antitussive, expectorant and antiasthmatic activities of verticinone-bile acids salts].

    PubMed

    Xu, Fang-Zhou; Zhang, Yong-Hui; Ruan, Han-Li; Pi, Hui-Fang; Chen, Chang; Wu, Ji-Zhou

    2007-03-01

    To search for potential drugs with potent antitussive, expectorant, antiasthmatic activities and low toxicity, a series of verticinone-bile acids salts were prepared based on the clearly elucidated antitussive, expectorant and antiasthmatic activities of verticinone in bulbs of Fritillaria and different bile acids in Snake Bile. The antitussive, expectorant and antiasthmatic activities of these verticinone-bile acid salts were then screened with different animal models. Ver-CA (verticinone-cholic acid salt) and Ver-CDCA (verticinone-chenodeoxycholic acid salt) showed much more potent activities than other compounds. The bioactivities of Ver-CA and Ver-CDCA are worthy to be intensively studied, and it is also deserved to pay much attention to their much more potent antitussive effects than codeine phosphate. In order to elucidate whether they have synergistic effect and attenuated toxicity, their activities will be continuously compared with single verticinone, cholic acid and chenodeoxycholic acid at the same doses on different animal models. The application of "combination principles" in traditional Chinese medicinal formulations may be a novel way in triditional Chinese medicine research and discovery.

  3. Steroid binding to Autotaxin links bile salts and lysophosphatidic acid signalling.

    PubMed

    Keune, Willem-Jan; Hausmann, Jens; Bolier, Ruth; Tolenaars, Dagmar; Kremer, Andreas; Heidebrecht, Tatjana; Joosten, Robbie P; Sunkara, Manjula; Morris, Andrew J; Matas-Rico, Elisa; Moolenaar, Wouter H; Oude Elferink, Ronald P; Perrakis, Anastassis

    2016-01-01

    Autotaxin (ATX) generates the lipid mediator lysophosphatidic acid (LPA). ATX-LPA signalling is involved in multiple biological and pathophysiological processes, including vasculogenesis, fibrosis, cholestatic pruritus and tumour progression. ATX has a tripartite active site, combining a hydrophilic groove, a hydrophobic lipid-binding pocket and a tunnel of unclear function. We present crystal structures of rat ATX bound to 7α-hydroxycholesterol and the bile salt tauroursodeoxycholate (TUDCA), showing how the tunnel selectively binds steroids. A structure of ATX simultaneously harbouring TUDCA in the tunnel and LPA in the pocket, together with kinetic analysis, reveals that bile salts act as partial non-competitive inhibitors of ATX, thereby attenuating LPA receptor activation. This unexpected interplay between ATX-LPA signalling and select steroids, notably natural bile salts, provides a molecular basis for the emerging association of ATX with disorders associated with increased circulating levels of bile salts. Furthermore, our findings suggest potential clinical implications in the use of steroid drugs. PMID:27075612

  4. Steroid binding to Autotaxin links bile salts and lysophosphatidic acid signalling

    PubMed Central

    Keune, Willem-Jan; Hausmann, Jens; Bolier, Ruth; Tolenaars, Dagmar; Kremer, Andreas; Heidebrecht, Tatjana; Joosten, Robbie P.; Sunkara, Manjula; Morris, Andrew J.; Matas-Rico, Elisa; Moolenaar, Wouter H.; Oude Elferink, Ronald P.; Perrakis, Anastassis

    2016-01-01

    Autotaxin (ATX) generates the lipid mediator lysophosphatidic acid (LPA). ATX-LPA signalling is involved in multiple biological and pathophysiological processes, including vasculogenesis, fibrosis, cholestatic pruritus and tumour progression. ATX has a tripartite active site, combining a hydrophilic groove, a hydrophobic lipid-binding pocket and a tunnel of unclear function. We present crystal structures of rat ATX bound to 7α-hydroxycholesterol and the bile salt tauroursodeoxycholate (TUDCA), showing how the tunnel selectively binds steroids. A structure of ATX simultaneously harbouring TUDCA in the tunnel and LPA in the pocket, together with kinetic analysis, reveals that bile salts act as partial non-competitive inhibitors of ATX, thereby attenuating LPA receptor activation. This unexpected interplay between ATX-LPA signalling and select steroids, notably natural bile salts, provides a molecular basis for the emerging association of ATX with disorders associated with increased circulating levels of bile salts. Furthermore, our findings suggest potential clinical implications in the use of steroid drugs. PMID:27075612

  5. Molecular interactions between lecithin and bile salts/acids in oils and their effects on reverse micellization.

    PubMed

    Njauw, Ching-Wei; Cheng, Chih-Yang; Ivanov, Viktor A; Khokhlov, Alexei R; Tung, Shih-Huang

    2013-03-26

    It has been known that the addition of bile salts to lecithin organosols induces the formation of reverse wormlike micelles and that the worms are similar to long polymer chains that entangle each other to form viscoelastic solutions. In this study, we further investigated the effects of different bile salts and bile acids on the growth of lecithin reverse worms in cyclohexane and n-decane. We utilized rheological and small-angle scattering techniques to analyze the properties and structures of the reverse micelles. All of the bile salts can transform the originally spherical lecithin reverse micelles into wormlike micelles and their rheological behaviors can be described by the single-relaxation-time Maxwell model. However, their efficiencies to induce the worms are different. In contrast, before phase separation, bile acids can induce only short cylindrical micelles that are not long enough to impart viscoelasticity. We used Fourier transform infrared spectroscopy to investigate the interactions between lecithin and bile salts/acids and found that different bile salts/acids employ different functional groups to form hydrogen bonds with lecithin. Such effects determine the relative positions of the bile salts/acids in the headgroups of lecithin, thus resulting in varying efficiencies to alter the effective critical packing parameter for the formation of wormlike micelles. This work highlights the importance of intermolecular interactions in molecular self-assembly.

  6. Is bile salt-dependent lipase concentration in serum of any help in pancreatic cancer diagnosis?

    PubMed

    Lombardo, D; Montalto, G; Roudani, S; Mas, E; Laugier, R; Sbarra, V; Abouakil, N

    1993-09-01

    The diagnostic value of bile salt-dependent lipase for pancreatic diseases was tested in sera of 187 patients. Of these patients, 76 suffered from pancreatic carcinoma, 43 from nonmalignant liver diseases (cirrhosis and chronic hepatitis), 18 from acute pancreatitis, and 20 from chronic pancreatitis. The remaining subjects were controls without pancreatic pathology. Bile salt-dependent lipase was determined by a sandwich enzyme-linked immunosorbent assay using polyclonal antibodies. Amylase and CA 19-9 antigen were also determined. In sera from control patients, the mean level of bile salt-dependent lipase was 1.5 micrograms/L. This level is quite similar to that of patients with benign liver diseases (1.1 micrograms/L) and with chronic pancreatitis (1.4 micrograms/L), but it was raised to 3.5 micrograms/L in patients with acute pancreatitis and decreased to 0.5 microgram/L in subjects with pancreatic adenocarcinoma. Thirty percent of control subjects and 73% of cancer patients had a bile salt-dependent lipase serum level below the cutoff value of 0.5 microgram/L. In acute pancreatitis, 11 of 16 subjects had levels above 1.5 micrograms/L. Amylase level largely increased in acute pancreatitis but was normal in all other groups. Concerning CA 19-9 antigen, 65% of control patients and > 80% of patients with nonmalignant pancreatic or liver diseases had normal levels. In sera from cancer patients, 80% presented with high levels. Accordingly, 36 of 38 patients with pancreatic cancer had either low serum levels of bile salt-dependent lipase (< 0.5 microgram/L) or high values of CA 19-9 antigen (> 37 U/ml; sensitivity 95%).(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Potency of individual bile acids to regulate bile acid synthesis and transport genes in primary human hepatocyte cultures.

    PubMed

    Liu, Jie; Lu, Hong; Lu, Yuan-Fu; Lei, Xiaohong; Cui, Julia Yue; Ellis, Ewa; Strom, Stephen C; Klaassen, Curtis D

    2014-10-01

    Bile acids (BAs) are known to regulate their own homeostasis, but the potency of individual bile acids is not known. This study examined the effects of cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA) and ursodeoxycholic acid (UDCA) on expression of BA synthesis and transport genes in human primary hepatocyte cultures. Hepatocytes were treated with the individual BAs at 10, 30, and 100μM for 48 h, and RNA was extracted for real-time PCR analysis. For the classic pathway of BA synthesis, BAs except for UDCA markedly suppressed CYP7A1 (70-95%), the rate-limiting enzyme of bile acid synthesis, but only moderately (35%) down-regulated CYP8B1 at a high concentration of 100μM. BAs had minimal effects on mRNA of two enzymes of the alternative pathway of BA synthesis, namely CYP27A1 and CYP7B1. BAs increased the two major target genes of the farnesoid X receptor (FXR), namely the small heterodimer partner (SHP) by fourfold, and markedly induced fibroblast growth factor 19 (FGF19) over 100-fold. The BA uptake transporter Na(+)-taurocholate co-transporting polypeptide was unaffected, whereas the efflux transporter bile salt export pump was increased 15-fold and OSTα/β were increased 10-100-fold by BAs. The expression of the organic anion transporting polypeptide 1B3 (OATP1B3; sixfold), ATP-binding cassette (ABC) transporter G5 (ABCG5; sixfold), multidrug associated protein-2 (MRP2; twofold), and MRP3 (threefold) were also increased, albeit to lesser degrees. In general, CDCA was the most potent and effective BA in regulating these genes important for BA homeostasis, whereas DCA and CA were intermediate, LCA the least, and UDCA ineffective.

  8. Effects of novel bile salts on cholesterol metabolism in rats and guinea-pigs.

    PubMed

    Fears, R; Brown, R; Ferres, H; Grenier, F; Tyrrell, A W

    1990-11-01

    Novel bile salts (quaternary ammonium conjugates) inhibited cholic acid binding and transport in everted ileal sacs in vitro. The cationic piperazine conjugate of lithocholic acid (di-iodide salt, compound 8, BRL 39924A) appeared most active, inhibiting binding by 29% and transport by 59% in guinea-pig ileum (200 microM). BRL 39924A also inhibited taurocholate uptake into guinea-pig ileal sacs and cholate uptake into rat ileal sacs and was selected for further study in vivo. In hyperlipidaemic rats, BRL 39924A significantly raised cholesterol 7 alpha-hydroxylase activity and decreased hepatic accumulation of exogenous cholic acid. HDL cholesterol concentration in the serum increased and the level of VLDL plus LDL cholesterol decreased. In hyperlipidaemic guinea-pigs. BRL 39924A lowered serum total cholesterol and triglyceride levels. Although metabolic changes were less than those achieved with the bile acid sequestrant, cholestyramine, the doses of BRL 39924A used were much lower (100-500 mg/kg body wt). Selective inhibition of receptor mediated bile acid uptake may be associated with local side-effects but these novel bile salts are useful pharmacological tools to examine the effects of receptor blockade on lipoprotein metabolism. PMID:2242032

  9. Sex differences in the bile acid composition of human bile: Studies in patients with and without gallstones

    PubMed Central

    Fisher, M. M.; Yousef, I. M.

    1973-01-01

    The bile acid composition of human gallbladder bile was studied in 83 subjects, 20 of each sex without discernible hepatobiliary disease, and 20 men and 23 women with cholelithiasis. The bile acids were measured by combined thin-layer and gas-liquid chromatography. In the bile of patients without cholelithiasis the molar percent of cholic acid was significantly greater in men while that of chenodeoxycholic acid was significantly greater in women. In the bile of patients with cholelithiasis the concentration of total bile acids was reduced in both sexes but there was no sex difference in the molar percent of any of the bile acids. The molar percent of CDCA (both glycine and taurine conjugates) was reduced in women, while the molar percent of CA (only the glycine conjugate) was reduced in men. PMID:4728947

  10. A single-component multidrug transporter of the major facilitator superfamily is part of a network that protects Escherichia coli from bile salt stress.

    PubMed

    Paul, Stephanie; Alegre, Kamela O; Holdsworth, Scarlett R; Rice, Matthew; Brown, James A; McVeigh, Paul; Kelly, Sharon M; Law, Christopher J

    2014-05-01

    Resistance to high concentrations of bile salts in the human intestinal tract is vital for the survival of enteric bacteria such as Escherichia coli. Although the tripartite AcrAB-TolC efflux system plays a significant role in this resistance, it is purported that other efflux pumps must also be involved. We provide evidence from a comprehensive suite of experiments performed at two different pH values (7.2 and 6.0) that reflect pH conditions that E. coli may encounter in human gut that MdtM, a single-component multidrug resistance transporter of the major facilitator superfamily, functions in bile salt resistance in E. coli by catalysing secondary active transport of bile salts out of the cell cytoplasm. Furthermore, assays performed on a chromosomal ΔacrB mutant transformed with multicopy plasmid encoding MdtM suggested a functional synergism between the single-component MdtM transporter and the tripartite AcrAB-TolC system that results in a multiplicative effect on resistance. Substrate binding experiments performed on purified MdtM demonstrated that the transporter binds to cholate and deoxycholate with micromolar affinity, and transport assays performed on inverted vesicles confirmed the capacity of MdtM to catalyse electrogenic bile salt/H(+) antiport.

  11. Influence of Phosphatidylcholine and Calcium on Self-Association and Bile Salt Mixed Micellar Binding of the Natural Bile Pigment, Bilirubin Ditaurate.

    PubMed

    Neubrand, Michael W; Carey, Martin C; Laue, Thomas M

    2015-11-17

    Recently [Neubrand, M. W., et al. (2015) Biochemistry 54, 1542-1557], we determined a concentration-dependent monomer-dimer-tetramer equilibrium in aqueous bilirubin ditaurate (BDT) solutions and explored the nature of high-affinity binding of BDT monomers with monomers and micelles of the common taurine-conjugated bile salts (BS). We now investigate, employing complementary physicochemical methods, including fluorescence emission spectrophotometry and quasi-elastic light scattering spectroscopy, the influence of phosphatidylcholine (PC), the predominant phospholipid of bile and calcium, the major divalent biliary cation, on these self-interactions and heterointeractions. We have used short-chain, lyso and long-chain PC species as models and contrasted our results with those of parallel studies employing unconjugated bilirubin (UCB) as the fully charged dianion. Both bile pigments interacted with the zwitterionic headgroup of short-chain lecithins, forming water-soluble (BDT) and insoluble ion-pair complexes (UCB), respectively. Upon micelle formation, BDT monomers apparently remained at the headgroup mantle of short-chain PCs, but the ion pairs with UCB became internalized within the micelle's hydrophobic core. BDT interacted with the headgroups of unilamellar egg yolk (EY) PC vesicles; however, with the simultaneous addition of CaCl2, a reversible aggregation took place, but not vesicle fusion. With mixed EYPC/BS micelles, BDT became bound to the hydrophilic surface (as with simple BS micelles), and in turn, both BDT and BS bound calcium, but not other divalent cations. The calcium complexation of BDT and BS was enhanced strongly with increases in micellar EYPC, suggesting calcium-mediated cross-bridging of hydrophilic headgroups at the micelle's surface. Therefore, the physicochemical binding of BDT to BS in an artificial bile medium is influenced not only by BS species and concentration but also by long-chain PCs and calcium ions that exert a specific rather

  12. Influence of Phosphatidylcholine and Calcium on Self-Association and Bile Salt Mixed Micellar Binding of the Natural Bile Pigment, Bilirubin Ditaurate.

    PubMed

    Neubrand, Michael W; Carey, Martin C; Laue, Thomas M

    2015-11-17

    Recently [Neubrand, M. W., et al. (2015) Biochemistry 54, 1542-1557], we determined a concentration-dependent monomer-dimer-tetramer equilibrium in aqueous bilirubin ditaurate (BDT) solutions and explored the nature of high-affinity binding of BDT monomers with monomers and micelles of the common taurine-conjugated bile salts (BS). We now investigate, employing complementary physicochemical methods, including fluorescence emission spectrophotometry and quasi-elastic light scattering spectroscopy, the influence of phosphatidylcholine (PC), the predominant phospholipid of bile and calcium, the major divalent biliary cation, on these self-interactions and heterointeractions. We have used short-chain, lyso and long-chain PC species as models and contrasted our results with those of parallel studies employing unconjugated bilirubin (UCB) as the fully charged dianion. Both bile pigments interacted with the zwitterionic headgroup of short-chain lecithins, forming water-soluble (BDT) and insoluble ion-pair complexes (UCB), respectively. Upon micelle formation, BDT monomers apparently remained at the headgroup mantle of short-chain PCs, but the ion pairs with UCB became internalized within the micelle's hydrophobic core. BDT interacted with the headgroups of unilamellar egg yolk (EY) PC vesicles; however, with the simultaneous addition of CaCl2, a reversible aggregation took place, but not vesicle fusion. With mixed EYPC/BS micelles, BDT became bound to the hydrophilic surface (as with simple BS micelles), and in turn, both BDT and BS bound calcium, but not other divalent cations. The calcium complexation of BDT and BS was enhanced strongly with increases in micellar EYPC, suggesting calcium-mediated cross-bridging of hydrophilic headgroups at the micelle's surface. Therefore, the physicochemical binding of BDT to BS in an artificial bile medium is influenced not only by BS species and concentration but also by long-chain PCs and calcium ions that exert a specific rather

  13. Formation of drug-bearing vesicles in mixed colloids of bile salts and phosphatidylcholine

    SciTech Connect

    Hjelm, R.P.; Mang, J.; Hofmann, A.F.; Schteingart, C.; Alkan-Onyuksel, H.; Ayd, S.

    1997-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors used small-angle neutron scattering to study drug interactions with mixed colloids of bile salt and phosphatidylcholine. Because the mixed colloids form liposomes spontaneously, this system is a model for drug-bile interactions that are important in understanding the efficacy of oral drug formulations and in advanced applications for liposome drug delivery systems. The authors studied particle formation in incorporation of enzymatic products formed in the gut and the effects of cholesteric drugs and taxol on vesicle formation. The studies show that particle morphology is not affected by inclusion of most cholesteric drugs and taxol, and is not affected by incorporation of the products of enzymatic action. The findings suggest that particle form is important for the physiological function of bile and they are beginning to show which drugs affect liposome formation.

  14. Colipase enhances hydrolysis of dietary triglycerides in the absence of bile salts.

    PubMed

    Bläckberg, L; Hernell, O; Bengtsson, G; Olivecrona, T

    1979-11-01

    This study explores how dietary lipids are digested when intraduodenal bile salts are low or absent. Long-chain triglycerides emulsified with phosphatidylcholine were found to be hydrolyzed very slowly by pancreatic lipase alone, as if the surface layer of phospholipids enveloping the triglycerides impeded the action of the enzyme. Colipase enhanced triglyceride hydrolysis severalfold, both when added before or after the lipase. Hydrolysis became even more rapid when the emulsion was first incubated with pancreatic phospholipase. Hydrolysis of long-chain triglycerides was also severely impeded when other proteins were added to the system, probably because they adsorbed to the oil-water interface of the emulsion droplets. It was previously known that bile salts can relieve such inhibition, presumably by desorbing the adsorbed proteins. Colipase was found to enhance hydrolysis severalfold in a dose-dependent manner even in the absence of bile salts, i.e., it could partially or completely relieve the inhibition depending upon the amount and the type of inhibitory protein added to the system. Prior exposure of a protein-coated triglyceride emulsion to another lipase also enhanced the rate at which pancreatic lipase could then hydrolyze the lipids. Most dietary triglycerides are probably presented for intestinal digestion in emulsions covered by proteins and/or phospholipids. These emulsions would be hydrolyzed slowly by pancreatic lipase alone. However, through the action of the lipase in stomach contents and of pancreatic phospholipase and through the lipolysis-promoting effects of collipase, these triglycerices can be rather efficiently hydrolyzed, even in the absence of bile salts.

  15. Protective action of luminal bile salts in necrotizing acute pancreatitis in mice.

    PubMed Central

    Gomez, G; Townsend, C M; Green, D W; Rajaraman, S; Uchida, T; Greeley, G H; Soloway, R D; Thompson, J C

    1990-01-01

    Bile salts in the intestinal lumen act to inhibit the release of cholecystokinin (CCK). Recent studies have shown that CCK may play a permissive role in the development of acute pancreatitis. In this study, the amount of luminal bile salts in female Swiss Webster mice was either decreased by feeding 4% (wt/wt) cholestyramine or increased by feeding 0.5% sodium taurocholate for 1 wk. Plasma levels of CCK were stimulated by cholestyramine and inhibited by taurocholate. Then, acute pancreatitis was induced either by caerulein injections, or by feeding a choline-deficient, ethionine-supplemented (CDE) diet. Feeding of cholestyramine significantly decreased survival from 25% to 0% in the CDE pancreatitis, and increased the magnitude of elevation of serum amylase levels and the extent of pancreatic necrosis in both models of pancreatitis; CCK-receptor blockade with CR-1409 completely abolished the adverse effects of cholestyramine. In contrast, feeding of taurocholate significantly increased survival to 100% and decreased the elevation of serum amylase and pancreatic necrosis; CCK-8 antagonized these actions of taurocholate. Luminal bile salts appear to provide a physiologic protection against necrotizing pancreatitis, at least in part, both by inhibiting the release of CCK and by promoting resistance of the pancreas to CCK excessive stimulation in vivo. Images PMID:1694866

  16. ATP-dependent bile-salt transport in canalicular rat liver plasma-membrane vesicles.

    PubMed Central

    Stieger, B; O'Neill, B; Meier, P J

    1992-01-01

    The present study identifies and characterizes a novel ATP-dependent bile-salt transport system in isolated canalicular rat liver plasma-membrane (cLPM) vesicles. ATP (1-5 mM) stimulated taurocholate uptake into cLPM vesicles between 6- and 8-fold above equilibrium uptake values (overshoot) and above values for incubations in the absence of ATP. The ATP-dependent portion of taurocholate uptake was 2-fold higher in the presence of equilibrated KNO3 as compared with potassium gluconate, indicating that the stimulatory effect of ATP was not due to the generation of an intravesicular positive membrane potential. Saturation kinetics revealed a very high affinity (Km approximately 2.1 microM) of the system for taurocholate. The system could only minimally be stimulated by nucleotides other than ATP. Furthermore, it was preferentially inhibited by conjugated univalent bile salts. Further strong inhibitory effects were observed with valinomycin, oligomycin, 4,4'-di-isothiocyano-2,2'-stilbene disulphonate, sulphobromophthalein, leukotriene C4 and N-ethylmaleimide, whereas nigericin, vanadate, GSH, GSSG and daunomycin exerted only weak inhibitory effects or none at all. These results indicate the presence of a high-affinity primary ATP-dependent bile-salt transport system in cLPM vesicles. This transport system might be regulated in vivo by the number of carriers present at the perspective transport site(s), which, in addition to the canalicular membrane, might also include pericanalicular membrane vesicles. PMID:1599411

  17. Multifaceted applications of bile salts in pharmacy: an emphasis on nanomedicine

    PubMed Central

    Elnaggar, Yosra SR

    2015-01-01

    The human body has long provided pharmaceutical science with biomaterials of interesting applications. Bile salts (BSs) are biomaterials reminiscent of traditional surfactants with peculiar structure and self-assembled topologies. In the pharmaceutical field, BSs were employed on the basis of two different concepts. The first concept exploited BSs’ metabolic and homeostatic functions in disease modulation, whereas the second one utilized BSs’ potential to modify drug-delivery characteristics, which recently involved nanotechnology. This review is the first to gather major pharmaceutical applications of BSs from endogenous organotropism up to integration into nanomedicine, with a greater focus on the latter domain. Endogenous applications highlighted the role of BS in modulating hypercholesterolemia and cancer therapy in view of enterohepatic circulation. In addition, recent BS-integrated nanomedicines have been surveyed, chiefly size-tunable cholate nanoparticles, BS-lecithin mixed micelles, bilosomes, probilosomes, and surface-engineered bilosomes. A greater emphasis has been laid on nanosystems for vaccine and cancer therapy. The comparative advantages of BS-integrated nanomedicines over conventional nanocarriers have been noted. Paradoxical effects, current pitfalls, future perspectives, and opinions have also been outlined. PMID:26109855

  18. Tolerance of Bifidobacterium human isolates to bile, acid and oxygen.

    PubMed

    Andriantsoanirina, Valérie; Allano, Solène; Butel, Marie José; Aires, Julio

    2013-06-01

    Bifidobacteria are part of the human gastrointestinal microbiota and are used as probiotics in functional food products because of their health promoting properties. However, only few data are available on the phenotypic characteristics displayed by human bifidobacteria strain populations. In this study we compared the in vitro tolerance to acid, bile and oxygen of the largest number of independent human intestinal strains. Bile and acid tolerance varied among species and independent strains within a species: B. adolescentis strains were the most tolerant to bile followed by Bifidobacterium longum and B. breve; B. longum, B. breve and B. dentium showed the highest viability levels after exposure to acid pH. Oxygen tolerance was largely distributed among intestinal bifidobacteria: B. longum, B. breve and B. bifidum showed the highest oxygen tolerance. B. adolescentis showed the highest susceptibility to acid and oxygen stresses. The present study gave us the opportunity to update our knowledge about the phenotypic characteristics of human intestinal bifidobacteria. B. longum and B. breve harboured the best tolerance to oxygen, bile and acid stresses. Based on such biological characters, B. longum and B. breve species showed the highest interest in terms of potential selection of human probiotics.

  19. Purification and Characterization of Conjugated Bile Salt Hydrolase from Bifidobacterium longum BB536.

    PubMed

    Grill, J; Schneider, F; Crociani, J; Ballongue, J

    1995-07-01

    Bifidobacterium species deconjugate taurocholic, taurodeoxycholic, taurochenodeoxycholic, glycocholic, glycodeoxycholic, and glycochenodeoxycholic acids. The enzyme level increases in the growth phase. No increase in activity is observed for the cytoplasmic enzyme after addition of conjugated bile acids to a stationary-phase culture. Conjugated bile salt hydrolase (BSH) was purified from Bifidobacterium longum BB536. Its apparent molecular mass in denaturing polyacrylamide gel electrophoresis was ca. 40,000 Da. The intact enzyme had a relative molecular weight of ca. 250,000 as determined by gel filtration chromatography, suggesting that the native BSH of B. longum is probably a hexamer. The purified enzyme is active towards both glycine and taurine conjugates of cholate, deoxycholate, and chenodeoxycholate. The pH optimum is in the range of 5.5 to 6.5. A loss of BSH activity is observed after incubation at temperatures higher than 42(deg)C; at 60(deg)C, 50% of the BSH activity is lost. The importance of free sulfhydryl groups at the enzyme active center is suggested. For B. longum BB536, no significant difference in the initial rate of deconjugation and enzymatic efficiency appears between bile salts. The enzymatic efficiency is higher for B. longum BB536 than for other genera. In this paper, a new method which permits a display of BSH activity directly on polyacrylamide gels is described; this method confirms the molecular weight obtained for B. longum BB536 BSH.

  20. Optimizing Human Bile Preparation for Two-Dimensional Gel Electrophoresis

    PubMed Central

    Cheng, Hao-Tsai; Sung, Chang-Mu; Pai, Betty Chien-Jung; Liu, Nai-Jen; Chen, Carl PC

    2016-01-01

    Aims. Bile is an important body fluid which assists in the digestion of fat and excretion of endogenous and exogenous compounds. In the present study, an improved sample preparation for human bile was established. Methods and Material. The method involved acetone precipitation followed by protein extraction using commercially available 2D Clean-Up kit. The effectiveness was evaluated by 2-dimensional electrophoresis (2DE) profiling quality, including number of protein spots and spot distribution. Results. The total protein of bile fluid in benign biliary disorders was 0.797 ± 0.465 μg/μL. The sample preparation method using acetone precipitation first followed by 2D Clean-Up kit protein extraction resulted in better quality of 2DE gel images in terms of resolution as compared with other sample preparation methods. Using this protocol, we obtained approximately 558 protein spots on the gel images and with better protein spots presentation of haptoglobin, serum albumin, serotransferrin, and transthyretin. Conclusions. Protein samples of bile prepared using acetone precipitation followed by 2D Clean-Up kit exhibited high protein resolution and significant protein profile. This optimized protein preparation protocol can effectively concentrate bile proteins, remove abundant proteins and debris, and yield clear presentation of nonabundant proteins and its isoforms on 2-dimensional electrophoresis gel images. PMID:26966686

  1. Light-scattering spectroscopy of native bile

    NASA Astrophysics Data System (ADS)

    Prygun, Natalya P.; Korolevich, Alexander N.

    1995-01-01

    Light scattering spectroscopy (LSS) was used to measure particle sizes in fresh human gallbladder bile of patients with gallstones. The recent experiments suggest the presence of a novel, bile salt-independent, mode of cholesterol transport in saturated human bile. Cholesterol is carried in large phospholipid vesicles with approximate diameter of 75 nm. It was shown that under experimental conditions these vesicles were able to dissolve up to 80% of the biliary cholesterol at low bile salt concentrations. A lecithin lamellar phase has already been suggested as a cholesterol carrier and recently vesicles were reported in model bile solutions and in native bile. Due to its nonperturbing nature, the technique of LLS has in recent years become widely applied to the study of micellar systems and, in particular, has been used to systematically investigate aqueous biliary lipid systems. LSS was employed to characterize the size, shape thermodynamics and interactions of bile salts micelle.

  2. Monohydroxy bile salt sulfates: tauro-3 beta-hydroxy-5-cholenoate-3-sulfate induces intrahepatic cholestasis in rats

    SciTech Connect

    Mathis, U.; Karlaganis, G.; Preisig, R.

    1983-09-01

    The biologic effects of sulfation of tauro-3 beta-hydroxy-5-cholenoate and of taurolithocholate were compared. Equimolar amounts (100 nmol/min X 100 g body wt) of the following were administered intravenously to male Sprague-Dawley rats over a 180-min period: taurolithocholate, (/sup 14/C)taurolithocholate-3-sulfate, tauro-3 beta-hydroxy-5-cholenoate, (/sup 14/C)tauro-3 beta-hydroxy-5-cholenoate-3-sulfate, its combination with taurocholate, and a saline-albumin solution (control). Sulfation of taurolithocholate and of tauro-3 beta-hydroxy-5-cholenoate only prevented the cholestatic effect of the former. Bile flow during infusion of (/sup 14/C)tauro-3 beta-hydroxy-5-cholenoate-3-sulfate was reduced by 80% at the end of the experiment. A dose-dependent bile flow reduction was demonstrated. Recovery of the administered bile acid was 3% in urine, 13% in serum, 23% in the liver tissue, and 52% in bile, respectively. Excretion of biliary cholesterol and phospholipids was significantly reduced during the first hour of infusion. Coadministration of taurocholate abolished the cholestatic effect and enhanced the renal excretion of the sulfated bile salt. These data suggest that (a) the cholestatic effect of tauro-3 beta-hydroxy-5-cholenoate-3-sulfate is comparable with or may even exceed the effect of taurolithocholate and (b) although sulfation renders some bile salts more water soluble, it does not prevent the cholestatic effect of all monohydroxy bile salts.

  3. Recombinant Bile Salt-Stimulated Lipase in Preterm Infant Feeding: A Randomized Phase 3 Study

    PubMed Central

    Casper, Charlotte; Hascoet, Jean-Michel; Ertl, Tibor; Gadzinowski, Janusz S.; Carnielli, Virgilio; Rigo, Jacques; Lapillonne, Alexandre; Couce, María L.; Vågerö, Mårten; Palmgren, Ingrid; Timdahl, Kristina; Hernell, Olle

    2016-01-01

    Introduction Feeding strategies are critical for healthy growth in preterm infants. Bile salt-stimulated lipase (BSSL), present in human milk, is important for fat digestion and absorption but is inactivated during pasteurization and absent in formula. This study evaluated if recombinant human BSSL (rhBSSL) improves growth in preterm infants when added to formula or pasteurized breast milk. Patients and Methods LAIF (Lipase Added to Infant Feeding) was a randomized, double-blind, placebo-controlled phase 3 study in infants born before 32 weeks of gestation. The primary efficacy variable was growth velocity (g/kg/day) during 4 weeks intervention. Follow-up visits were at 3 and 12 months. The study was performed at 54 centers in 10 European countries. Results In total 415 patients were randomized (rhBSSL n = 207, placebo n = 208), 410 patients were analyzed (rhBSSL n = 206, placebo n = 204) and 365 patients were followed until 12 months. Overall, there was no significantly improved growth velocity during rhBSSL treatment compared to placebo (16.77 vs. 16.56 g/kg/day, estimated difference 0.21 g/kg/day, 95% CI [-0.40; 0.83]), nor were secondary endpoints met. However, in a predefined subgroup, small for gestational age infants, there was a significant effect on growth in favor of rhBSSL during treatment. The incidence of adverse events was higher in the rhBSSL group during treatment. Conclusions Although this study did not meet its primary endpoint, except in a subgroup of infants small for gestational age, and there was an imbalance in short-term safety, these data provide insights in nutrition, growth and development in preterm infants. Trial Registration ClinicalTrials.gov NCT01413581 PMID:27244221

  4. Bile salt/phospholipid mixed micelle precursor pellets prepared by fluid-bed coating

    PubMed Central

    Dong, Fuxia; Xie, Yunchang; Qi, Jianping; Hu, Fuqiang; Lu, Yi; Li, Sanming; Wu, Wei

    2013-01-01

    Bile salt/phospholipid mixed micelles (MMs) are potent carriers used for oral absorption of drugs that are poorly soluble in water; however, there are many limitations associated with liquid formulations. In the current study, the feasibility of preparing bile salt/phospholipid MM precursor (preMM) pellets with high oral bioavailability, using fluid-bed coating technology, was examined. In this study, fenofibrate (FB) and sodium deoxycholate (SDC) were used as the model drug and the bile salt, respectively. To prepare the MMs and to serve as the micellular carrier, a weight ratio of 4:6 was selected for the sodium deoxycholate/phospholipids based on the ternary phase diagram. Polyethylene glycol (PEG) 6000 was selected as the dispersion matrix for precipitation of the MMs onto pellets, since it can enhance the solubilizing ability of the MMs. Coating of the MMs onto the pellets using the fluid-bed coating technology was efficient and the pellets were spherical and intact. MMs could be easily reconstituted from preMM pellets in water. Although they existed in a crystalline state in the preMM pellets, FB could be encapsulated into the reconstituted MMs, and the MMs were redispersed better than solid dispersion pellets (FB:PEG = 1:3) and Lipanthyl®. The redispersibility of the preMM pellets increased with the increase of the FB/PEG/micellar carrier. PreMM pellets with a FB:PEG:micellar carrier ratio of 1:1.5:1.5 showed 284% and 145% bioavailability relative to Lipanthyl® and solid dispersion pellets (FB:PEG = 1:3), respectively. Fluid-bed coating technology has considerable potential for use in preparing sodium deoxycholate/phospholipid preMM pellets, with enhanced oral bioavailability for poorly water-soluble drugs. PMID:23641154

  5. Bile salt-induced intermolecular disulfide bond formation activates Vibrio cholerae virulence.

    PubMed

    Yang, Menghua; Liu, Zhi; Hughes, Chambers; Stern, Andrew M; Wang, Hui; Zhong, Zengtao; Kan, Biao; Fenical, William; Zhu, Jun

    2013-02-01

    To be successful pathogens, bacteria must often restrict the expression of virulence genes to host environments. This requires a physical or chemical marker of the host environment as well as a cognate bacterial system for sensing the presence of a host to appropriately time the activation of virulence. However, there have been remarkably few such signal-sensor pairs identified, and the molecular mechanisms for host-sensing are virtually unknown. By directly applying a reporter strain of Vibrio cholerae, the causative agent of cholera, to a thin layer chromatography (TLC) plate containing mouse intestinal extracts, we found two host signals that activate virulence gene transcription. One of these was revealed to be the bile salt taurocholate. We then show that a set of bile salts cause dimerization of the transmembrane transcription factor TcpP by inducing intermolecular disulfide bonds between cysteine (C)-207 residues in its periplasmic domain. Various genetic and biochemical analyses led us to propose a model in which the other cysteine in the periplasmic domain, C218, forms an inhibitory intramolecular disulfide bond with C207 that must be isomerized to form the active C207-C207 intermolecular bond. We then found bile salt-dependent effects of these cysteine mutations on survival in vivo, correlating to our in vitro model. Our results are a demonstration of a mechanism for direct activation of the V. cholerae virulence cascade by a host signal molecule. They further provide a paradigm for recognition of the host environment in pathogenic bacteria through periplasmic cysteine oxidation.

  6. Isolation, Identification and Partial Characterization of a Lactobacillus casei Strain with Bile Salt Hydrolase Activity from Pulque.

    PubMed

    González-Vázquez, R; Azaola-Espinosa, A; Mayorga-Reyes, L; Reyes-Nava, L A; Shah, N P; Rivera-Espinoza, Y

    2015-12-01

    The aim of this study was to isolate, from pulque, Lactobacillus spp. capable of survival in simulated gastrointestinal stress conditions. Nine Gram-positive rods were isolated; however, only one strain (J57) shared identity with Lactobacillus and was registered as Lactobacillus casei J57 (GenBank accession: JN182264). The other strains were identified as Bacillus spp. The most significant observation during the test of tolerance to simulated gastrointestinal conditions (acidity, gastric juice and bile salts) was that L. casei J57 showed a rapid decrease (p ≤ 0.05) in the viable population at 0 h. Bile salts were the stress condition that most affected its survival, from which deoxycholic acid and the mix of bile salts (oxgall) were the most toxic. L. casei J57 showed bile salt hydrolase activity over primary and secondary bile salts as follows: 44.91, 671.72, 45.27 and 61.57 U/mg to glycocholate, taurocholate, glycodeoxycholate and taurodeoxycholate. In contrast, the control strain (L. casei Shirota) only showed activity over tauroconjugates. These results suggest that L. casei J57 shows potential for probiotic applications. PMID:26566892

  7. Isolation, Identification and Partial Characterization of a Lactobacillus casei Strain with Bile Salt Hydrolase Activity from Pulque.

    PubMed

    González-Vázquez, R; Azaola-Espinosa, A; Mayorga-Reyes, L; Reyes-Nava, L A; Shah, N P; Rivera-Espinoza, Y

    2015-12-01

    The aim of this study was to isolate, from pulque, Lactobacillus spp. capable of survival in simulated gastrointestinal stress conditions. Nine Gram-positive rods were isolated; however, only one strain (J57) shared identity with Lactobacillus and was registered as Lactobacillus casei J57 (GenBank accession: JN182264). The other strains were identified as Bacillus spp. The most significant observation during the test of tolerance to simulated gastrointestinal conditions (acidity, gastric juice and bile salts) was that L. casei J57 showed a rapid decrease (p ≤ 0.05) in the viable population at 0 h. Bile salts were the stress condition that most affected its survival, from which deoxycholic acid and the mix of bile salts (oxgall) were the most toxic. L. casei J57 showed bile salt hydrolase activity over primary and secondary bile salts as follows: 44.91, 671.72, 45.27 and 61.57 U/mg to glycocholate, taurocholate, glycodeoxycholate and taurodeoxycholate. In contrast, the control strain (L. casei Shirota) only showed activity over tauroconjugates. These results suggest that L. casei J57 shows potential for probiotic applications.

  8. Effect of bile salts stress on protein synthesis of Lactobacillus casei Zhang revealed by 2-dimensional gel electrophoresis.

    PubMed

    Wu, R; Sun, Z; Wu, J; Meng, H; Zhang, H

    2010-08-01

    Lactobacillus casei Zhang, isolated from koumiss in Inner Mongolia of China, is known from previous findings to be tolerant to bile salts. Bile salts secreted by mammals act as a natural antibacterial barrier and may serve as a component of innate immunity, as they have limited antagonistic effect against resident microflora. In this work, we compared the growth and protein expression patterns of L. casei Zhang with and without bile salts. Twenty-six proteins were found to be differentially expressed using 2-dimensional gel electrophoresis. Peptide mass fingerprinting was used to identify these proteins. Further verification by using real-time, quantitative reverse transcription-PCR and bioinformatics analysis showed that the implicated pathways are involved with a complex physiological response under bile salts stress, particularly including cell protection (DnaK and GroEL), modifications in cell membranes (NagA, GalU, and PyrD), and key components of central metabolism (PFK, PGM, CysK, LuxS, PepC, and EF-Tu). These results provide insight on the protein expression pattern of L. casei under bile salts stress and offer a new perspective for the molecular mechanisms involved in stress tolerance and adaptation of bacteria. PMID:20655455

  9. Bile salt inhibition of host cell damage by Clostridium difficile toxins.

    PubMed

    Darkoh, Charles; Brown, Eric L; Kaplan, Heidi B; DuPont, Herbert L

    2013-01-01

    Virulent Clostridium difficile strains produce toxin A and/or toxin B that are the etiological agents of diarrhea and pseudomembranous colitis. Treatment of C. difficile infections (CDI) has been hampered by resistance to multiple antibiotics, sporulation, emergence of strains with increased virulence, recurrence of the infection, and the lack of drugs that preserve or restore the colonic bacterial flora. As a result, there is new interest in non-antibiotic CDI treatments. The human conjugated bile salt taurocholate was previously shown in our laboratory to inhibit C. difficile toxin A and B activities in an in vitro assay. Here we demonstrate for the first time in an ex vivo assay that taurocholate can protect Caco-2 colonic epithelial cells from the damaging effects of the C. difficile toxins. Using caspase-3 and lactate dehydrogenase assays, we have demonstrated that taurocholate reduced the extent of toxin B-induced apoptosis and cell membrane damage. Confluent Caco-2 cells cultured with toxin B induced elevated caspase-3 activity. Remarkably, addition of 5 mM taurocholate reduced caspase-3 activity in cells treated with 2, 4, 6, and 12 µg/ml of toxin B by 99%, 78%, 64%, and 60%, respectively. Furthermore, spent culture medium from Caco-2 cells incubated with both toxin B and taurocholate exhibited significantly decreased lactate dehydrogenase activity compared to spent culture medium from cells incubated with toxin B only. Our results suggest that the mechanism of taurocholate-mediated inhibition functions at the level of toxin activity since taurocholate did not affect C. difficile growth and toxin production. These findings open up a new avenue for the development of non-antibiotic therapeutics for CDI treatment.

  10. Bile Salt Inhibition of Host Cell Damage by Clostridium Difficile Toxins

    PubMed Central

    Darkoh, Charles; Brown, Eric L.; Kaplan, Heidi B.; DuPont, Herbert L.

    2013-01-01

    Virulent Clostridium difficile strains produce toxin A and/or toxin B that are the etiological agents of diarrhea and pseudomembranous colitis. Treatment of C. difficile infections (CDI) has been hampered by resistance to multiple antibiotics, sporulation, emergence of strains with increased virulence, recurrence of the infection, and the lack of drugs that preserve or restore the colonic bacterial flora. As a result, there is new interest in non-antibiotic CDI treatments. The human conjugated bile salt taurocholate was previously shown in our laboratory to inhibit C. difficile toxin A and B activities in an in vitro assay. Here we demonstrate for the first time in an ex vivo assay that taurocholate can protect Caco-2 colonic epithelial cells from the damaging effects of the C. difficile toxins. Using caspase-3 and lactate dehydrogenase assays, we have demonstrated that taurocholate reduced the extent of toxin B-induced apoptosis and cell membrane damage. Confluent Caco-2 cells cultured with toxin B induced elevated caspase-3 activity. Remarkably, addition of 5 mM taurocholate reduced caspase-3 activity in cells treated with 2, 4, 6, and 12 µg/ml of toxin B by 99%, 78%, 64%, and 60%, respectively. Furthermore, spent culture medium from Caco-2 cells incubated with both toxin B and taurocholate exhibited significantly decreased lactate dehydrogenase activity compared to spent culture medium from cells incubated with toxin B only. Our results suggest that the mechanism of taurocholate-mediated inhibition functions at the level of toxin activity since taurocholate did not affect C. difficile growth and toxin production. These findings open up a new avenue for the development of non-antibiotic therapeutics for CDI treatment. PMID:24244530

  11. Dissolution rates of model gallstones in human and animal biles and importance of interfacial resistance.

    PubMed

    Molokhia, A M; Hofmann, A F; Higuchi, W I; Tuchinda, M; Feld, K; Prakongpan, S; Danzinger, R G

    1977-08-01

    Cholesterol monohydrate dissolution kinetics in human gallbladder bile were studied to determine the magnitudes of the in vitro dissolution rates, the rate resistances in human gallbladder bile, and the extent that the interfacial resistance is the rate-determining factor. Dissolution rate studies also were conducted using human duodenal bile and animal bile for comparison. The dissolution rate resistance, R, ranged from 10(4) sec/cm for chicken bile to 10(4)-10(6) sec/cm for human bile. Interfacial resistance was the rate-determining factor for essentially all results. Where chemical composition data were obtained, the R values for the human bile samples were consistent with predictions made from the simulated bile studies. In two human gallbladder specimens having low bile acid-lecithin molar ratios (i.e., 2.9 and 2.3), very high R values of 1.9 X 10(5) and 4.1 X 10(5) sec/cm were found. These values were in good agreement with the findings in the simulated bile studies and suggest that stone dissolution in patients with low bile acid-lecithin ratios may proceed very slowly, even when the bile is highly undersaturated with respect to cholesterol.

  12. Bile acid-induced necrosis in primary human hepatocytes and in patients with obstructive cholestasis

    SciTech Connect

    Woolbright, Benjamin L.; Dorko, Kenneth; Antoine, Daniel J.; Clarke, Joanna I.; Gholami, Parviz; Li, Feng; Kumer, Sean C.; Schmitt, Timothy M.; Forster, Jameson; Fan, Fang; Jenkins, Rosalind E.; Park, B. Kevin; Hagenbuch, Bruno; Olyaee, Mojtaba; Jaeschke, Hartmut

    2015-03-15

    Accumulation of bile acids is a major mediator of cholestatic liver injury. Recent studies indicate bile acid composition between humans and rodents is dramatically different, as humans have a higher percent of glycine conjugated bile acids and increased chenodeoxycholate content, which increases the hydrophobicity index of bile acids. This increase may lead to direct toxicity that kills hepatocytes, and promotes inflammation. To address this issue, this study assessed how pathophysiological concentrations of bile acids measured in cholestatic patients affected primary human hepatocytes. Individual bile acid levels were determined in serum and bile by UPLC/QTOFMS in patients with extrahepatic cholestasis with, or without, concurrent increases in serum transaminases. Bile acid levels increased in serum of patients with liver injury, while biliary levels decreased, implicating infarction of the biliary tracts. To assess bile acid-induced toxicity in man, primary human hepatocytes were treated with relevant concentrations, derived from patient data, of the model bile acid glycochenodeoxycholic acid (GCDC). Treatment with GCDC resulted in necrosis with no increase in apoptotic parameters. This was recapitulated by treatment with biliary bile acid concentrations, but not serum concentrations. Marked elevations in serum full-length cytokeratin-18, high mobility group box 1 protein (HMGB1), and acetylated HMGB1 confirmed inflammatory necrosis in injured patients; only modest elevations in caspase-cleaved cytokeratin-18 were observed. These data suggest human hepatocytes are more resistant to human-relevant bile acids than rodent hepatocytes, and die through necrosis when exposed to bile acids. These mechanisms of cholestasis in humans are fundamentally different to mechanisms observed in rodent models. - Highlights: • Cholestatic liver injury is due to cytoplasmic bile acid accumulation in hepatocytes. • Primary human hepatocytes are resistant to BA-induced injury

  13. Periplasmic Export of Bile Salt Hydrolase in Escherichia coli by the Twin-Arginine Signal Peptides.

    PubMed

    Dong, Zixing; Zhang, Juan; Du, Guocheng; Chen, Jian; Li, Huazhong; Lee, Byonghoon

    2015-09-01

    Bile salt hydrolase (BSH, EC 3.5.1.24) is considered as an ideal way with lower cost and less side effects to release the risk of coronary heart disease caused by hypercholesterolemia. As bile salt hydrolase from Lactobacillus plantarum BBE7 could not be efficiently exported by PelB signal peptide of the general secretory (Sec) pathway, three twin-arginine signal peptides from twin-arginine translocation (Tat) pathway were synthesized, fused with bsh gene, inserted into expression vectors pET-20b(+) and pET-22b(+), and transformed into four different Escherichia coli hosts, respectively. Among the 24 recombinant bacteria obtained, E. coli BL21 (DE3) pLysS (pET-20b(+)-dmsA-bsh) showed the highest BSH activity in periplasmic fraction, which was further increased to 1.21 ± 0.03 U/mL by orthogonal experimental design. And, signal peptide dimethyl sulfoxide reductase subunit DmsA (DMSA) had the best activity of exported BSH. More importantly, the presence of BSH in the periplasm had proven to be caused by the export rather than cell leakage. For the first time, we report the periplasmic expression of BSH by signal peptides from the Tat pathway. This will lay a solid foundation for the purification and biochemical characterization of BSH from the supernatant, and strategies adopted here could be used for the periplasmic expression of other proteins in E. coli.

  14. Endogenous bile acid disposition in rat and human sandwich-cultured hepatocytes

    SciTech Connect

    Marion, Tracy L.; Perry, Cassandra H.; St Claire, Robert L.; Brouwer, Kim L.R.

    2012-05-15

    Sandwich-cultured hepatocytes (SCH) are used commonly to investigate hepatic transport protein-mediated uptake and biliary excretion of substrates. However, little is known about the disposition of endogenous bile acids (BAs) in SCH. In this study, four endogenous conjugated BAs common to rats and humans [taurocholic acid (TCA), glycocholic acid (GCA), taurochenodeoxycholic acid (TCDCA), and glycochenodeoxycholic acid (GCDCA)], as well as two BA species specific to rodents (α- and β-tauromuricholic acid; α/β TMCA), were profiled in primary rat and human SCH. Using B-CLEAR{sup ®} technology, BAs were measured in cells + bile canaliculi, cells, and medium of SCH by LC-MS/MS. Results indicated that, just as in vivo, taurine-conjugated BA species were predominant in rat SCH, while glycine-conjugated BAs were predominant in human SCH. Total intracellular BAs remained relatively constant over days in culture in rat SCH. Total BAs in control (CTL) cells + bile, cells, and medium were approximately 3.4, 2.9, and 8.3-fold greater in human than in rat. The estimated intracellular concentrations of the measured total BAs were 64.3 ± 5.9 μM in CTL rat and 183 ± 56 μM in CTL human SCH, while medium concentrations of the total BAs measured were 1.16 ± 0.21 μM in CTL rat SCH and 9.61 ± 6.36 μM in CTL human SCH. Treatment of cells for 24 h with 10 μM troglitazone (TRO), an inhibitor of the bile salt export pump (BSEP) and the Na{sup +}-taurocholate cotransporting polypeptide (NTCP), had no significant effect on endogenous BAs measured at the end of the 24-h culture period, potentially due to compensatory mechanisms that maintain BA homeostasis. These data demonstrate that BAs in SCH are similar to in vivo, and that SCH may be a useful in vitro model to study alterations in BA disposition if species differences are taken into account. -- Highlights: ► Bile acids (BAs) were measured in rat and human sandwich-cultured hepatocytes (SCH). ► Cell and medium BA

  15. Regulation of human class I alcohol dehydrogenases by bile acids

    PubMed Central

    Langhi, Cédric; Pedraz-Cuesta, Elena; Haro, Diego; Marrero, Pedro F.; Rodríguez, Joan C.

    2013-01-01

    Class I alcohol dehydrogenases (ADH1s) are the rate-limiting enzymes for ethanol and vitamin A (retinol) metabolism in the liver. Because previous studies have shown that human ADH1 enzymes may participate in bile acid metabolism, we investigated whether the bile acid-activated nuclear receptor farnesoid X receptor (FXR) regulates ADH1 genes. In human hepatocytes, both the endogenous FXR ligand chenodeoxycholic acid and synthetic FXR-specific agonist GW4064 increased ADH1 mRNA, protein, and activity. Moreover, overexpression of a constitutively active form of FXR induced ADH1A and ADH1B expression, whereas silencing of FXR abolished the effects of FXR agonists on ADH1 expression and activity. Transient transfection studies and electrophoretic mobility shift assays revealed functional FXR response elements in the ADH1A and ADH1B proximal promoters, thus indicating that both genes are direct targets of FXR. These findings provide the first evidence for direct connection of bile acid signaling and alcohol metabolism. PMID:23772048

  16. Regulation of human class I alcohol dehydrogenases by bile acids.

    PubMed

    Langhi, Cédric; Pedraz-Cuesta, Elena; Haro, Diego; Marrero, Pedro F; Rodríguez, Joan C

    2013-09-01

    Class I alcohol dehydrogenases (ADH1s) are the rate-limiting enzymes for ethanol and vitamin A (retinol) metabolism in the liver. Because previous studies have shown that human ADH1 enzymes may participate in bile acid metabolism, we investigated whether the bile acid-activated nuclear receptor farnesoid X receptor (FXR) regulates ADH1 genes. In human hepatocytes, both the endogenous FXR ligand chenodeoxycholic acid and synthetic FXR-specific agonist GW4064 increased ADH1 mRNA, protein, and activity. Moreover, overexpression of a constitutively active form of FXR induced ADH1A and ADH1B expression, whereas silencing of FXR abolished the effects of FXR agonists on ADH1 expression and activity. Transient transfection studies and electrophoretic mobility shift assays revealed functional FXR response elements in the ADH1A and ADH1B proximal promoters, thus indicating that both genes are direct targets of FXR. These findings provide the first evidence for direct connection of bile acid signaling and alcohol metabolism.

  17. The unique ligand binding features of subfamily-II iLBPs with respect to bile salts and related drugs.

    PubMed

    Favretto, Filippo; Ceccon, Alberto; Zanzoni, Serena; D'Onofrio, Mariapina; Ragona, Laura; Molinari, Henriette; Assfalg, Michael

    2015-04-01

    Intracellular lipid binding proteins (iLBPs) are a family of evolutionarily related small cytoplasmic proteins implicated in the transcellular transport of lipophilic ligands. Subfamily-II iLBPs include the liver fatty acid binding protein (L-FABP), and the ileal and the liver and ileal bile acid binding proteins (L-BABP and I-BABP). Atomic-level investigations during the past 15-20 years have delivered relevant information on bile acid binding by this protein group, revealing unique features including binding cooperativity, promiscuity, and site selectivity. Using NMR spectroscopy and other biophysical techniques, our laboratories have contributed to an understanding of the molecular determinants of some of these properties and their generality among proteins from different animal species. We focused especially on formation of heterotypic complexes, considering the mixed compositions of physiological bile acid pools. Experiments performed with synthetic bile acid derivatives showed that iLBPs could act as targets for cell-specific contrast agents and, more generally, as effective carriers of amphiphilic drugs. This review collects the major findings related to bile salt interactions with iLBPs aiming to provide keys for a deeper understanding of protein-mediated intracellular bile salt trafficking. PMID:25468388

  18. Structural alterations in lecithin-cholesterol vesicles following interactions with monomeric and micellar bile salts: physical-chemical basis for subselection of biliary lecithin species and aggregative states of biliary lipids during bile formation.

    PubMed

    Cohen, D E; Angelico, M; Carey, M C

    1990-01-01

    Using complementary physical-chemical methods including turbidimetry, quasielastic light scattering, gel filtration, and phase analysis, we examined the interactions between dilute concentrations of the common bile salt, taurochenodeoxycholate (TCDC), and uni- and multilamellar vesicles (MLVs) composed of defined molecular species of lecithin (L) and varying contents of cholesterol (Ch). Dissolution rates of MLVs with micellar TCDC, as assessed by turbidimetry, were more rapid with vesicles composed of sn-1 palmitoyl species, typical of biliary L, compared with those composed of the more hydrophobic sn-1 stearoyl species. Incorporation of Ch retarded MLV dissolution rates in proportion to the Ch content, and only at high Ch contents were dissolution rates appreciably influenced by the sn-2 fatty acid composition of L. When MLVs contained Ch in amounts characteristic of intracellular membranes (Ch/L approximately 0.1), the dissolution rates of the individual L species by TCDC accurately predicted the steady state L composition of human bile. TCDC interacted with small unilamellar L/Ch vesicles (SUVs) at concentrations well below, as well as appreciably above, its critical micellar concentration. In accordance with the TCDC-egg yolk L-H2O phase diagram, perimicellar concentrations of TCDC interacted with SUVs to form aggregates that were approximately twice the size of the SUVs. These were consistent with the formation of a dispersed hexagonal (rod-like) phase, which co-existed with aqueous bile salt (BS) monomers and either micellar or unilamellar SUV phases. Micellar TCDC completely solubilized SUVs as mixed micelles, putatively via this transient hexagonal phase. With modest Ch-supersaturation, dissolution was followed by the reemergence of a new vesicle population that coexisted metastably with mixed micelles. With high Ch supersaturation, TCDC extracted L and Ch molecules from SUVs in different proportions to form Ch-supersaturated mixed micelles and Ch

  19. Bile duct obstruction

    MedlinePlus

    ... the liver. It contains cholesterol, bile salts, and waste products such as bilirubin . Bile salts help your ... can lead to life-threatening infection and a dangerous buildup of bilirubin. If the blockage lasts a ...

  20. Bile Salts Modulate the Mucin-Activated Type VI Secretion System of Pandemic Vibrio cholerae

    PubMed Central

    Unterweger, Daniel; Diaz-Satizabal, Laura; Ogg, Stephen; Pukatzki, Stefan

    2015-01-01

    The causative agent of cholera, Vibrio cholerae, regulates its diverse virulence factors to thrive in the human small intestine and environmental reservoirs. Among this pathogen’s arsenal of virulence factors is the tightly regulated type VI secretion system (T6SS). This system acts as an inverted bacteriophage to inject toxins into competing bacteria and eukaryotic phagocytes. V. cholerae strains responsible for the current 7th pandemic activate their T6SS within the host. We established that T6SS-mediated competition occurs upon T6SS activation in the infant mouse, and that this system is functional under anaerobic conditions. When investigating the intestinal host factors mucins (a glycoprotein component of mucus) and bile for potential regulatory roles in controlling the T6SS, we discovered that once mucins activate the T6SS, bile acids can further modulate T6SS activity. Microbiota modify bile acids to inhibit T6SS-mediated killing of commensal bacteria. This interplay is a novel interaction between commensal bacteria, host factors, and the V. cholerae T6SS, showing an active host role in infection. PMID:26317760

  1. Bile Salts Modulate the Mucin-Activated Type VI Secretion System of Pandemic Vibrio cholerae.

    PubMed

    Bachmann, Verena; Kostiuk, Benjamin; Unterweger, Daniel; Diaz-Satizabal, Laura; Ogg, Stephen; Pukatzki, Stefan

    2015-01-01

    The causative agent of cholera, Vibrio cholerae, regulates its diverse virulence factors to thrive in the human small intestine and environmental reservoirs. Among this pathogen's arsenal of virulence factors is the tightly regulated type VI secretion system (T6SS). This system acts as an inverted bacteriophage to inject toxins into competing bacteria and eukaryotic phagocytes. V. cholerae strains responsible for the current 7th pandemic activate their T6SS within the host. We established that T6SS-mediated competition occurs upon T6SS activation in the infant mouse, and that this system is functional under anaerobic conditions. When investigating the intestinal host factors mucins (a glycoprotein component of mucus) and bile for potential regulatory roles in controlling the T6SS, we discovered that once mucins activate the T6SS, bile acids can further modulate T6SS activity. Microbiota modify bile acids to inhibit T6SS-mediated killing of commensal bacteria. This interplay is a novel interaction between commensal bacteria, host factors, and the V. cholerae T6SS, showing an active host role in infection.

  2. Molecular interactions of a model bile salt and porcine bile with (1,3:1,4)-β-glucans and arabinoxylans probed by (13)C NMR and SAXS.

    PubMed

    Gunness, Purnima; Flanagan, Bernadine M; Mata, Jitendra P; Gilbert, Elliot P; Gidley, Michael J

    2016-04-15

    Two main classes of interaction between soluble dietary fibres (SDFs), such as (1,3:1,4)-β-D-glucan (βG) and arabinoxylan (AX) and bile salt (BS) or diluted porcine bile, were identified by (13)C NMR and small angle X-ray scattering (SAXS). Small chemical shift differences of BS NMR resonances were consistent with effective local concentration or dilution of BS micelles mostly by βG, suggesting dynamic interactions; whilst the reduced line widths/intensities observed were mostly caused by wheat AX and the highest molecular size and concentrations of βG. SAXS showed evidence of changes in βG but not AX in the presence of BS micelles, at >13 nm length scale consistent with molecular level interactions. Thus intermolecular interactions between SDF and BS depend on both SDF source and its molecular weight and may occur alone or in combination. PMID:26617003

  3. Bile salt liposomes for enhanced lymphatic transport and oral bioavailability of paclitaxel.

    PubMed

    Zhang, Bin; Xue, Aiying; Zhang, Chen; Yu, Jinlong; Chen, Wen; Sun, Deqing

    2016-06-01

    Paclitaxel (PTX), a BCS class IV drug that is characterized by its poor solubility and is a substrate for P-glycoprotein, is one of the most widely used antineoplastic agents. However, oral administration of PTX for chemotherapy is highly challenging. The aim of this study was to develop bile-salt liposomes (BS-Lips) to enhance the absorption of PTX and thus improve its therapeutic outcome. The BS-Lips were prepared by the thin-film hydration method and characterized in terms of particle size and morphology. Drug release and in vitro stability in simulated gastrointestinal fluids and in media of different pH values were evaluated, as well as in vivo performance, including antitumor activity and pharmacokinetics in rats, with the plasma concentrations determined by a HPLC method. The PTX-loaded BS-Lips were successfully prepared with a diameter of approximately 150 nm and an entrapment efficiency of greater than 90 percent. Moreover, the BS-Lips were not affected by gastrointestinal enzymes or pH alternation, as evident from the unchanged particle size and the drug retained in BS-Lips after 6 h incubation. The insertion of bile salt into the lipid layer of liposomes increased the lymphatic transport of PTX by twofold. Importantly, BS-Lips increased the oral bioavailability of PTX by 2.5 and 4-fold, respectively, compared with conventional liposomes (Lips) and Taxol (free drug), thereby displaying a better inhibition of tumor growth that was similar to the group injected intravenously with Taxol. In conclusion, the BS-Lips represent promising vehicles for the oral delivery of PTX, thereby enabling an intravenous-to-oral switch for cancer chemotherapy. PMID:27455550

  4. Effects of bile salts and divalent cations on the adsorption of norfloxacin by agricultural soils.

    PubMed

    Kong, Xuesong; Feng, Shixiang; Zhang, Xu; Li, Yan

    2014-04-01

    The effects of bile salts (sodium cholate and sodium deoxycholate, 0-20 mmol/L), divalent cations (Ca(2+), Mg(2+), Cu(2+) and Zn(2+), 0-20 mmol/L) or pH (3.0-10.0) on the adsorption of norfloxacin by three selected soils (Paddy_H, Paddy_G and Red_J) were systematically studied. Soil adsorption of norfloxacin follows a pseudo second-order kinetics model, and the maximum adsorption capacity has been determined from the nonlinear fit of the Langmuir isotherm model to be 88.8, 88.1 and 63.0 μmol/g for the adsorption onto Paddy_H, Paddy_G and Red_J, respectively. The results indicate that norfloxacin has a high adsorption affinity for the agricultural soils tested and that the organic content of these soils have at least a slight influence on this adsorption. The adsorption of norfloxacin to soils was strongly dependent on pH and exhibited a maximum at approximately pH 6. The presence of divalent cations prominently suppressed the adsorption of norfloxacin by paddy soils, which followed an order of Cu(2+) > Mg(2+) > Ca(2+) > Zn(2+), and by red soil, which followed an order of Cu(2+) > Zn(2+) > Ca(2+) > Mg(2+). The adsorption of norfloxacin (by the soils studied) sharply decreased as the amount of bile salts was increased. For uncharged norfloxacin at environmentally relevant pH values, such factors as soil type, exogenous divalent cations and macromolecules significantly altered the environmental fate and transport of norfloxacin between aquatic and soil interfaces. PMID:25079415

  5. Effects of bile salts and divalent cations on the adsorption of norfloxacin by agricultural soils.

    PubMed

    Kong, Xuesong; Feng, Shixiang; Zhang, Xu; Li, Yan

    2014-04-01

    The effects of bile salts (sodium cholate and sodium deoxycholate, 0-20 mmol/L), divalent cations (Ca(2+), Mg(2+), Cu(2+) and Zn(2+), 0-20 mmol/L) or pH (3.0-10.0) on the adsorption of norfloxacin by three selected soils (Paddy_H, Paddy_G and Red_J) were systematically studied. Soil adsorption of norfloxacin follows a pseudo second-order kinetics model, and the maximum adsorption capacity has been determined from the nonlinear fit of the Langmuir isotherm model to be 88.8, 88.1 and 63.0 μmol/g for the adsorption onto Paddy_H, Paddy_G and Red_J, respectively. The results indicate that norfloxacin has a high adsorption affinity for the agricultural soils tested and that the organic content of these soils have at least a slight influence on this adsorption. The adsorption of norfloxacin to soils was strongly dependent on pH and exhibited a maximum at approximately pH 6. The presence of divalent cations prominently suppressed the adsorption of norfloxacin by paddy soils, which followed an order of Cu(2+) > Mg(2+) > Ca(2+) > Zn(2+), and by red soil, which followed an order of Cu(2+) > Zn(2+) > Ca(2+) > Mg(2+). The adsorption of norfloxacin (by the soils studied) sharply decreased as the amount of bile salts was increased. For uncharged norfloxacin at environmentally relevant pH values, such factors as soil type, exogenous divalent cations and macromolecules significantly altered the environmental fate and transport of norfloxacin between aquatic and soil interfaces.

  6. Effect of the structure of bile salt aggregates on the binding of aromatic guests and the accessibility of anions.

    PubMed

    Li, Rui; Carpentier, Eric; Newell, Edward D; Olague, Lana M; Heafey, Eve; Yihwa, Chang; Bohne, Cornelia

    2009-12-15

    The binding of naphthalene (Np), 1-ethylnaphthalene (EtNp), acenaphthene (AcN), and 1-naphthyl-1-ethanol (NpOH) as guests to the aggregates of sodium cholate (NaCh), taurocholate (NaTC), deoxycholate (NaDC), and deoxytaurocholate (NaTDC) was studied with the objective of determining how the structure of the bile salts affects the binding dynamics of guests and quenchers with the bile salt aggregates. Time-resolved and steady-state fluorescence experiments were used to determine the binding efficiency of the guests with the aggregates and were also employed to investigate the quenching of the singlet excited state of the guests by iodide anions. Quenching studies of the triplet excited states using laser flash photolysis were employed to determine the accessibility to the aggregate of nitrite anions, used as quenchers, and the dissociation rate constants of the guests from the bile salt aggregates. The binding efficiency of the guests to NaDC and NaTDC is higher than for NaCh and NaTC, and the protection efficiency is also higher for NaDC and NaTDC, in line with the larger aggregates formed for the latter bile salts. The formation of aggregates is in part driven by the structure of the guest, where an increased protection efficiency and residence time can be achieved by the introduction of short alkyl substituents (AcN or EtNp vs Np). NpOH was shown to be located in a very different environment in all four bile salts when compared to AcN, EtNp, and Np, suggesting that hydrogen bonding plays an important role in the formation of the aggregate around NpOH. PMID:19606836

  7. Bile Acid-Induced Necrosis in Primary Human Hepatocytes and in Patients with Obstructive Cholestasis

    PubMed Central

    Woolbright, Benjamin L.; Dorko, Kenneth; Antoine, Daniel J.; Clarke, Joanna I.; Gholami, Parviz; Li, Feng; Kumer, Sean C.; Schmitt, Timothy M.; Forster, Jameson; Fan, Fang; Jenkins, Rosalind E.; Park, B. Kevin; Hagenbuch, Bruno; Olyaee, Mojtaba; Jaeschke, Hartmut

    2015-01-01

    Accumulation of bile acids is a major mediator of cholestatic liver injury. Recent studies indicate bile acid composition between humans and rodents is dramatically different, as humans have a higher percent of glycine conjugated bile acids and increased chenodeoxycholate content, which increases the hydrophobicity index of bile acids. This increase may lead to direct toxicity that kills hepatocytes, and promotes inflammation. To address this issue, this study assessed how pathophysiological concentrations of bile acids measured in cholestatic patients affected primary human hepatocytes. Individual bile acid levels were determined in serum and bile by UPLC/QTOFMS in patients with extrahepatic cholestasis with, or without, concurrent increases in serum transaminases. Bile acid levels increased in serum of patients with liver injury, while biliary levels decreased, implicating infarction of the biliary tracts. To assess bile acid-induced toxicity in man, primary human hepatocytes were treated with relevant concentrations, derived from patient data, of the model bile acid glycochenodeoxycholic acid (GCDC). Treatment with GCDC resulted in necrosis with no increase in apoptotic parameters. This was recapitulated by treatment with biliary bile acid concentrations, but not serum concentrations. Marked elevations in serum full-length cytokeratin-18, high mobility group box1 protein (HMGB1), and acetylated HMGB1 confirmed inflammatory necrosis in injured patients; only modest elevations in caspase-cleaved cytokeratin-18 were observed. These data suggest human hepatocytes are more resistant to human-relevant bile acids than rodent hepatocytes, and die through necrosis when exposed to bile acids. These mechanisms of cholestasis in humans are fundamentally different to mechanisms observed in rodent models. PMID:25636263

  8. Arsenic bioaccessibility upon gastrointestinal digestion is highly determined by its speciation and lipid-bile salt interactions.

    PubMed

    Alava, Pradeep; Du Laing, Gijs; Odhiambo, Moses; Verliefde, Arne; Tack, Filip; Van de Wiele, Tom R

    2013-01-01

    The release of arsenic (As) from a contaminated food matrix during gastrointestinal digestion, i.e., its bioaccessibility, is an important estimator of its bioavailability, and therefore also its health risk. In addition, As toxicity is primarily determined by its speciation and it is not clear how different As species behave during digestion in the upper digestive tract. Here, we evaluated to what extent digestive parameters like gastric pH and bile concentration, but also food matrix constituents affect the bioaccessibility of 8 As species (As(III), As(V), MMA(V), DMA(V), MMA(III), DMA(III), MMMTA(V), DMMTA(V)). Bioaccessibility of all As standards ranged between 85% and 90% under pH 1.8. Bioaccessibility of methylated and thiolated arsenicals was decreased from 85% to 50% with increasing gastric pH to 4, yet an increasing bile salts concentration up to 30 g/L lowered the bioaccessibility of inorganic species from 83% to 70% due to interaction with Fe present in bile salts. With respect to food matrices, we noted that the fiber content did not affect As bioaccessibility, yet the presence of fat resulted in an increased bioaccessibility of both inorganic and organic arsenicals in the presence of bile salts. With respect to inorganic arsenic, the intestinal presence of trivalent Fe appeared to be the predominant factor for bioaccessibility of iAs. These data demonstrate that species dependent bioaccessibility must be considered upon ingestion and gastrointestinal digestion. PMID:23442116

  9. APE1-mediated DNA damage repair provides survival advantage for esophageal adenocarcinoma cells in response to acidic bile salts.

    PubMed

    Hong, Jun; Chen, Zheng; Peng, Dunfa; Zaika, Alexander; Revetta, Frank; Washington, M Kay; Belkhiri, Abbes; El-Rifai, Wael

    2016-03-29

    Chronic Gastroesophageal Reflux Disease (GERD) is the main risk factor for the development of Barrett's esophagus (BE) and its progression to esophageal adenocarcinoma (EAC). Accordingly, EAC cells are subjected to high levels of oxidative stress and subsequent DNA damage. In this study, we investigated the expression and role of Apurinic/apyrimidinic endonuclease 1 (APE1) protein in promoting cancer cell survival by counteracting the lethal effects of acidic bile salts (ABS)-induced DNA damage. Immunohistochemistry analysis of human tissue samples demonstrated overexpression of APE1 in more than half of EACs (70 of 130), as compared to normal esophagus and non-dysplastic BE samples (P < 0.01). To mimic in vivo conditions, we treated in vitro cell models with a cocktail of ABS. The knockdown of endogenous APE1 in EAC FLO-1 cells significantly increased oxidative DNA damage (P < 0.01) and DNA single- and double-strand breaks (P < 0.01), whereas overexpression of APE1 in EAC OE33 cells reversed these effects. Annexin V/PI staining indicated that the APE1 expression in OE33 cells protects against ABS-induced apoptosis. In contrast, knockdown of endogenous APE1 in FLO-1 cells increased apoptosis under the same conditions. Mechanistic investigations indicated that the pro-survival function of APE1 was associated with the regulation of stress response c-Jun N-terminal protein kinase (JNK) and p38 kinases. Pharmacological inhibition of APE1 base excision repair (BER) function decreased cell survival and enhanced activation of JNK and p38 kinases by ABS. Our findings suggest that constitutive overexpression of APE1 in EAC may be an adaptive pro-survival mechanism that protects against the genotoxic lethal effects of bile reflux episodes. PMID:26934647

  10. Estrogen and Estrogen Receptor-α-Mediated Transrepression of Bile Salt Export Pump

    PubMed Central

    Chen, Yuan; Vasilenko, Alex; Song, Xiulong; Valanejad, Leila; Verma, Ruchi; You, Sangmin; Yan, Bingfang; Shiffka, Stephanie; Hargreaves, Leeza; Nadolny, Christina

    2015-01-01

    Among diseases unique to pregnancy, intrahepatic cholestasis of pregnancy is the most prevalent disorder with elevated serum bile acid levels. We have previously shown that estrogen 17β-estradiol (E2) transrepresses bile salt export pump (BSEP) through an interaction between estrogen receptor (ER)-α and farnesoid X receptor (FXR) and transrepression of BSEP by E2/ERα is an etiological contributing factor to intrahepatic cholestasis of pregnancy. Currently the mechanistic insights into such transrepression are not fully understood. In this study, the dynamics of coregulator recruitment to BSEP promoter after FXR activation and E2 treatment were established with quantitative chromatin immunoprecipitation assays. Coactivator peroxisome proliferator-activated receptor-γ coactivator-1 was predominantly recruited to the BSEP promoter upon FXR activation, and its recruitment was decreased by E2 treatment. Meanwhile, recruitment of nuclear receptor corepressor was markedly increased upon E2 treatment. Functional evaluation of ERα and ERβ chimeras revealed that domains AC of ERα are the determinants for ERα-specific transrepression on BSEP. Further studies with various truncated ERα proteins identified the domains in ERα responsible for ligand-dependent and ligand-independent transrepression. Truncated ERα-AD exhibited potent ligand-independent transrepressive activity, whereas ERα-CF was fully capable of transrepressing BSEP ligand dependently in vitro in Huh 7 cells and in vivo in mice. Both ERα-AD and ERα-CF proteins were associated with FXR in the coimmunoprecipitation assays. In conclusion, E2 repressed BSEP expression through diminishing peroxisome proliferator-activated receptor-γ coactivator-1 recruitment with a concurrent increase in nuclear receptor corepressor recruitment to the BSEP promoter. Domains AD and CF in ERα mediated ligand-independent and ligand-dependent transrepression on BSEP, respectively, through interacting with FXR. PMID:25675114

  11. Biliary proteins. Unique inhibitors of cholesterol crystal nucleation in human gallbladder bile.

    PubMed Central

    Holzbach, R T; Kibe, A; Thiel, E; Howell, J H; Marsh, M; Hermann, R E

    1984-01-01

    The onset time for cholesterol crystal nucleation of supersaturated normal human gallbladder biles is consistently prolonged when compared with biles from patients with cholesterol gallstone disease. Investigation of the factor(s) responsible for the suspended supersaturation (metastability) of normal human biles revealed that model bile solutions of cholesterol saturation index (CSI) and molar lipid composition identical to individual gallbladder bile specimens had much shorter crystal nucleation times, i.e., exhibited decreased metastability. Unsaturated normal biles, after supplementation with lecithin, cholesterol, and sodium taurocholate to a 'standard' supersaturated lipid composition, also demonstrated nucleation times three- to 15-fold longer than the comparable standard model bile. Total lipid extracts of normal biles, however, when similarly supplemented, did not differ in nucleation time from the control model solution. Gallbladder biles were fractionated by gel chromatography and the eluted fractions were pooled into two fractions. The fractions eluting in about the first 25% of the included volume when mixed with the supersaturated standard model bile induced a modest increase in nucleation time of approximately 1.5 times the control value. The fractions eluting in the second 25% of the included volume and which contained all of the bile lipids, were concentrated and supplemented with lipids to the standard composition. The nucleation times of these supplements were 3-10 times longer than the control nucleation times. Delipidated bile protein mixtures, purified by discontinuous sucrose gradient centrifugation, were recombined with purified lipids at the standard composition used previously. The nucleation times of these mixtures were significantly prolonged to the same extent as those associated with the second chromatographic fraction. These observations demonstrate that the delayed onset (inhibition) of cholesterol crystal nucleation observed in

  12. Cost effectiveness of adjuvant bile salt treatment in extracorporeal shock wave lithotripsy for the treatment of gall bladder stones.

    PubMed

    Nicholl, J P; Ross, B; Milner, P C; Brazier, J E; Westlake, L; Kohler, B; Frost, E; Williams, B T; Johnson, A G

    1994-09-01

    The relative cost effectiveness of adjuvant urso and chenodeoxycholic acid treatment in extracorporeal shockwave lithotripsy (ESWL) has been assessed as part of a pragmatic randomised controlled trial of ESWL as a treatment of gall bladder stones. Of the first patients with gall stone volume < 4 cm3 randomised to ESWL in the main trial, 24 were randomised to have ESWL alone and 26 to have adjuvant bile acid treatment, one of whom died before the end of the 12 month follow up period. At 12 months after treatment, differences in gall stone clearance between ESWL alone (3/24 (13%) clear, 5 (21%) referred for surgery) and ESWL and bile acids (6/25 (24%) clear, 2 (8%) referred for surgery) were not significant (p = 0.36, log rank test). Patients in both groups had substantial and significant health gains (according to biliary pain frequency and severity, Nottingham Health Profile scores, visual analogue scale symptom scores, and complications) but there were no significant differences between the groups. Improvements in both groups usually occurred within a few weeks of treatment and were unrelated to gall stone clearance. Costs were greater in the bile salt group (95% confidence intervals for estimated cost difference: 90 pounds to 630 pounds). If the purpose of treatment is symptom relief rather than gall stone clearance then adjuvant bile salt treatment seems to be unnecessary.

  13. Upregulation of miRNA-143, -145, -192, and -194 in esophageal epithelial cells upon acidic bile salt stimulation.

    PubMed

    Bus, P; Siersema, P D; Verbeek, R E; van Baal, J W P M

    2014-08-01

    Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus that occurs because of chronic gastroesophageal reflux. Previous studies have identified BE-specific microRNAs (miRNAs) in comparison with normal squamous epithelium (SQ). We hypothesized that BE-specific miRNAs could be induced in esophageal SQ cells by exposure to acid and/or bile salts. We aimed to determine whether BE-specific miRNAs are upregulated in an esophageal SQ cell line (Het-1A) in an environment with acid and/or bile salts and whether this is nuclear factor-κB (NF-κB) dependent. Acid and/or bile salt incubations were performed in Het-1A cells. Experiments were performed with or without inhibiting the NF-κB pathway. Quantitative reverse transcriptase polymerase chain reaction was performed to determine expression of miRNA-143, -145, -192, -194, cyclo-oxygenase-2 (COX2), mucin 2 (MUC2), and sex determining region Y-box 9. For validation, we determined levels of these miRNAs in biopsies from patients with reflux esophagitis and normal SQ. Significantly increased expression levels of miRNA-143 (2.7-fold), -145 (2.6-fold), -192 (2.0-fold), -194 (2.2-fold), COX2, MUC2, and sex determining region Y-box 9 were found upon acidic bile salt incubation, but not upon acid or bile salt alone. NF-κB pathway inhibition significantly decreased miRNA-143, -192, -194, COX2, and MUC2 expression. Additionally, miRNA-143, -145 and -194 expression was increased in reflux esophagitis biopsies compared with normal SQ, but no changes were found in miRNA-192 expression. Our findings suggest that upregulation of BE-specific miRNAs by acidic bile may be an early event in the transition of SQ to BE and that their expression is partly regulated by the NF-κB pathway. PMID:24006894

  14. Upregulation of miRNA-143, -145, -192, and -194 in esophageal epithelial cells upon acidic bile salt stimulation.

    PubMed

    Bus, P; Siersema, P D; Verbeek, R E; van Baal, J W P M

    2014-08-01

    Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus that occurs because of chronic gastroesophageal reflux. Previous studies have identified BE-specific microRNAs (miRNAs) in comparison with normal squamous epithelium (SQ). We hypothesized that BE-specific miRNAs could be induced in esophageal SQ cells by exposure to acid and/or bile salts. We aimed to determine whether BE-specific miRNAs are upregulated in an esophageal SQ cell line (Het-1A) in an environment with acid and/or bile salts and whether this is nuclear factor-κB (NF-κB) dependent. Acid and/or bile salt incubations were performed in Het-1A cells. Experiments were performed with or without inhibiting the NF-κB pathway. Quantitative reverse transcriptase polymerase chain reaction was performed to determine expression of miRNA-143, -145, -192, -194, cyclo-oxygenase-2 (COX2), mucin 2 (MUC2), and sex determining region Y-box 9. For validation, we determined levels of these miRNAs in biopsies from patients with reflux esophagitis and normal SQ. Significantly increased expression levels of miRNA-143 (2.7-fold), -145 (2.6-fold), -192 (2.0-fold), -194 (2.2-fold), COX2, MUC2, and sex determining region Y-box 9 were found upon acidic bile salt incubation, but not upon acid or bile salt alone. NF-κB pathway inhibition significantly decreased miRNA-143, -192, -194, COX2, and MUC2 expression. Additionally, miRNA-143, -145 and -194 expression was increased in reflux esophagitis biopsies compared with normal SQ, but no changes were found in miRNA-192 expression. Our findings suggest that upregulation of BE-specific miRNAs by acidic bile may be an early event in the transition of SQ to BE and that their expression is partly regulated by the NF-κB pathway.

  15. Survival of Bifidobacterium longum immobilized in calcium alginate beads in simulated gastric juices and bile salt solution.

    PubMed

    Lee, K Y; Heo, T R

    2000-02-01

    Bifidobacterium longum KCTC 3128 and HLC 3742 were independently immobilized (entrapped) in calcium alginate beads containing 2, 3, and 4% sodium alginate. When the bifidobacteria entrapped in calcium alginate beads were exposed to simulated gastric juices and a bile salt solution, the death rate of the cells in the beads decreased proportionally with an increase in both the alginate gel concentration and bead size. The initial cell numbers in the beads affected the numbers of survivors after exposure to these solutions; however, the death rates of the viable cells were not affected. Accordingly, a mathematical model was formulated which expressed the influences of several parameters (gel concentration, bead size, and initial cell numbers) on the survival of entrapped bifidobacteria after sequential exposure to simulated gastric juices followed by a bile salt solution. The model proposed in this paper may be useful for estimating the survival of bifidobacteria in beads and establishing optimal entrapment conditions.

  16. Organized media for fluorescence analysis of complex samples: Comparison of bile salt and conventional detergent micelles in coal liquids

    SciTech Connect

    Ritenour Hertz, P.M.; McGown, L.B. )

    1992-12-01

    Accurate quantitative determinations are often difficult to obtain from fluorescence analysis of complex samples due to sample matrix effects and intermolecular interactions between solutes. Organized media can be used to minimize these unwanted processes without physical separation or extraction of the analytes from the sample matrix by isolating the analyte molecules in a uniform microenvironment within the sample. The advantages of bile salt micellar media over conventional detergent micelles are demonstrated for analysis of coal liquids. The bile salt media is shown to increase the sensitivity and dynamic range of fluorescence measurements relative to simple ethanolic solutions, without promoting ground-state and excited-state interactions that occur in the detergent micellar media. 45 refs., 11 figs., 3 tabs.

  17. Niosomal carriers enhance oral bioavailability of carvedilol: effects of bile salt-enriched vesicles and carrier surface charge

    PubMed Central

    Arzani, Gelareh; Haeri, Azadeh; Daeihamed, Marjan; Bakhtiari-Kaboutaraki, Hamid; Dadashzadeh, Simin

    2015-01-01

    Carvedilol (CRV) is an antihypertensive drug with both alpha and beta receptor blocking activity used to preclude angina and cardiac arrhythmias. To overcome the low, variable oral bioavailability of CRV, niosomal formulations were prepared and characterized: plain niosomes (without bile salts), bile salt-enriched niosomes (bilosomes containing various percentages of sodium cholate or sodium taurocholate), and charged niosomes (negative, containing dicetyl phosphate and positive, containing hexadecyl trimethyl ammonium bromide). All formulations were characterized in terms of encapsulation efficiency, size, zeta potential, release profile, stability, and morphology. Various formulations were administered orally to ten groups of Wistar rats (n=6 per group). The plasma levels of CRV were measured by a validated high-performance liquid chromatography (HPLC) method and pharmacokinetic properties of different formulations were characterized. Contribution of lymphatic transport to the oral bioavailability of niosomes was also investigated using a chylomicron flow-blocking approach. Of the bile salt-enriched vesicles examined, bilosomes containing 20% sodium cholate (F2) and 30% sodium taurocholate (F5) appeared to give the greatest enhancement of intestinal absorption. The relative bioavailability of F2 and F5 formulations to the suspension was estimated to be 1.84 and 1.64, respectively. With regard to charged niosomes, the peak plasma concentrations (Cmax) of CRV for positively (F7) and negatively charged formulations (F10) were approximately 2.3- and 1.7-fold higher than after a suspension. Bioavailability studies also revealed a significant increase in extent of drug absorption from charged vesicles. Tissue histology revealed no signs of inflammation or damage. The study proved that the type and concentration of bile salts as well as carrier surface charge had great influences on oral bioavailability of niosomes. Blocking the lymphatic absorption pathway

  18. Transbuccal delivery of 5-aza-2 -deoxycytidine: effects of drug concentration, buffer solution, and bile salts on permeation.

    PubMed

    Mahalingam, Ravichandran; Ravivarapu, Harish; Redkar, Sanjeev; Li, Xiaoling; Jasti, Bhaskara R

    2007-07-13

    Delivery of 5-aza-2 -deoxycytidine (decitabine) across porcine buccal mucosa was evaluated as an alternative to the complex intravenous infusion regimen currently used to administer the drug. A reproducible high-performance liquid chromatography method was developed and optimized for the quantitative determination of this drug. Decitabine showed a concentration-dependent passive diffusion process across porcine buccal mucosa. An increase in the ionic strength of the phosphate buffer from 100 to 400 mM decreased the flux from 3.57 +/- 0.65 to 1.89 +/- 0.61 microg/h/cm2. Trihydroxy bile salts significantly enhanced the flux of decitabine at a 100 mM concentration (P > .05). The steady-state flux of decitabine in the presence of 100 mM of sodium taurocholate and sodium glycocholate was 52.65 +/- 9.48 and 85.22 +/- 7.61 microg/cm2/h, respectively. Two dihydroxy bile salts, sodium deoxytaurocholate and sodium deoxyglycocholate, showed better enhancement effect than did trihydroxy bile salts. A 38-fold enhancement in flux was achieved with 10 mM of sodium deoxyglycocholate.

  19. Computational investigation of enthalpy-entropy compensation in complexation of glycoconjugated bile salts with β-cyclodextrin and analogs.

    PubMed

    Tidemand, Kasper D; Schönbeck, Christian; Holm, René; Westh, Peter; Peters, Günther H

    2014-09-18

    The inclusion complexes of glycoconjugated bile salts with β-cyclodextrin (β-CD) and 2-hydroxypropyl-β-cyclodextrins (HP-β-CD) in aqueous solution were investigated by molecular dynamics simulations to provide a molecular explanation of the experimentally observed destabilizing effect of the HP substituents. Good agreement with experimental data was found with respect to penetration depths of CDs. An increased degree of HP substitution (DS) resulted in an increased probability of blocking the cavity opening, thereby hindering the bile salt from entering CD. Further, the residence time of water molecules in the cavity increased with the DS. Release of water from the cavity resulted in a positive enthalpy change, which correlates qualitatively with the experimentally determined increase in complexation enthalpy and contributes to the enthalpy-entropy compensation. The positive change in complexation entropy with DS was not able to compensate for this unfavorable change in enthalpy induced by the HP substituents, resulting in a destabilizing effect. This was found to originate from fixation of the HP substituents and decreased free rotation of the bile salts within the CD cavities.

  20. In vitro lipid peroxidation of intestinal bile salt-based nanoemulsions: potential role of antioxidants.

    PubMed

    Courraud, J; Charnay, C; Cristol, J P; Berger, J; Avallone, S

    2013-12-01

    Over the last decades, oxidative stress has been described as a deleterious phenomenon contributing to numerous noncommunicable diseases such as cardiovascular disease, diabetes, and cancers. As many authors ascribed the healthy effect of fruit and vegetable consumption mainly to their antioxidant contents, it has been hypothesized that their protection could occur from the gut. Therefore, the aim of this study was to develop an original and physiological model of nanoemulsions to study lipid peroxidation within the intestine and to assess the properties of potential antioxidants in this setting. Several nanoemulsions were compared in terms of physical characteristics and reactivity to 2,2'-azobis-(2-amidinopropane) hydrochloride (AAPH)-induced oxidation. Formulations included different types of lipids, a detergent (a conjugated bile salt or sodium dodecyl sulfate) and, finally, lipophilic antioxidants. Hemin and myoglobin were also tested as relevant potential oxidants. Fatty acid (FA) peroxidation was monitored by gas chromatography while malondialdehyde and antioxidant contents were measured by HPLC. Investigated nanoemulsions were composed of spherical or cylindrical mixed micelles, the latter being the least resistant to oxidation. In the experimental conditions, AAPH was the only efficient oxidant. Alpha-tocopherol and lutein significantly slowed FA degradation from 4 to 1 μM, respectively. On the contrary, beta-carotene did not show any protective capacity at 4 μM. In conclusion, the tested nanoemulsions were appropriate to assess antioxidant capacity during the intestinal phase of digestion.

  1. The Escherichia coli SOS gene dinF protects against oxidative stress and bile salts.

    PubMed

    Rodríguez-Beltrán, Jerónimo; Rodríguez-Rojas, Alexandro; Guelfo, Javier R; Couce, Alejandro; Blázquez, Jesús

    2012-01-01

    DNA is constantly damaged by physical and chemical factors, including reactive oxygen species (ROS), such as superoxide radical (O(2)(-)), hydrogen peroxide (H(2)O(2)) and hydroxyl radical (•OH). Specific mechanisms to protect and repair DNA lesions produced by ROS have been developed in living beings. In Escherichia coli the SOS system, an inducible response activated to rescue cells from severe DNA damage, is a network that regulates the expression of more than 40 genes in response to this damage, many of them playing important roles in DNA damage tolerance mechanisms. Although the function of most of these genes has been elucidated, the activity of some others, such as dinF, remains unknown. The DinF deduced polypeptide sequence shows a high homology with membrane proteins of the multidrug and toxic compound extrusion (MATE) family. We describe here that expression of dinF protects against bile salts, probably by decreasing the effects of ROS, which is consistent with the observed decrease in H(2)O(2)-killing and protein carbonylation. These results, together with its ability to decrease the level of intracellular ROS, suggests that DinF can detoxify, either direct or indirectly, oxidizing molecules that can damage DNA and proteins from both the bacterial metabolism and the environment. Although the exact mechanism of DinF activity remains to be identified, we describe for the first time a role for dinF. PMID:22523558

  2. Enhanced oral bioavailability of cyclosporine A by liposomes containing a bile salt

    PubMed Central

    Guan, Peipei; Lu, Yi; Qi, Jianping; Niu, Mengmeng; Lian, Ruyue; Hu, Fuqiang; Wu, Wei

    2011-01-01

    The main purpose of this study was to evaluate liposomes containing a bile salt, sodium deoxycholate (SDC), as oral drug delivery systems to enhance the oral bioavailability of the poorly water-soluble and poorly permeable drug, cyclosporine A (CyA). Liposomes composed of soybean phosphatidylcholine (SPC) and SDC were prepared by a thin-film dispersion method followed by homogenization. Several properties of the liposomes including particle size, polydispersity index, and entrapment efficiency were characterized. The in vitro release of CyA from these liposomes was less than 5% at 12 hours as measured by a dynamic dialysis method. The pharmacokinetic results in rats showed improved absorption of CyA in SPC/SDC liposomes, compared with CyA-loaded conventional SPC/cholesterol (Chol) liposomes and microemulsion-based Sandimmune Neoral®. The relative oral bioavailability of CyA-loaded SPC/SDC and SPC/Chol liposomes was 120.3% and 98.6%, respectively, with Sandimmun Neoral as the reference. The enhanced bioavailability of CyA was probably due to facilitated absorption by the liposomes containing SDC rather than improved release rate. PMID:21720508

  3. Enhanced oral absorption of insulin-loaded liposomes containing bile salts: a mechanistic study.

    PubMed

    Niu, Mengmeng; Tan, Ya'nan; Guan, Peipei; Hovgaard, Lars; Lu, Yi; Qi, Jianping; Lian, Ruyue; Li, Xiaoyang; Wu, Wei

    2014-01-01

    Liposomes containing bile salts (BS-liposomes) significantly enhanced the oral bioavailability of insulin (rhINS). However, the underlying absorption mechanisms have not been well understood yet. In this study, the transiting fate of the liposomes was first investigated using fluorescent imaging tools to confirm the effect of enhanced gastrointestinal stability. In order to obtain evidence of enhanced transcellular permeation, the interaction between BS-liposomes and the biomembrane was investigated in Caco-2 cell lines. BS-liposomes were found to be more stable in the gastrointestinal tract by showing prolonged residence time in comparison with conventional liposomes. BS-liposomes were significantly more effective for cellular uptake and transport of rhINS; and this effect was found to be size- and concentration-dependent. A good linear correlation was observed between the concentration of the liposomes and uptake/transport of rhINS. Confocal laser scanning microscopy visualization further validated the transcellular transit of BS-liposomes. The BS-liposomes showed little effect on cytotoxicity and did not induce apoptosis within 24h investigation. It was concluded that BS-liposomes showed improved in vivo residence time and enhanced permeation across the biomemebranes. Mechanisms of trans-enterocytic internalization could be proposed as an interpretation for enhanced absorption of insulin-loaded liposomes.

  4. Displacement of Drugs From Cyclodextrin Complexes by Bile Salts: A Suggestion of an Intestinal Drug-Solubilizing Capacity From an In Vitro Model.

    PubMed

    Olesen, Niels Erik; Westh, Peter; Holm, René

    2016-09-01

    The dosing of drugs in an aqueous cyclodextrin formulation requires sufficient amount of cyclodextrins to fully solubilize the drug, as described by Stella's cyclodextrin utility number (UCD). However, this framework does not take biopharmaceutical elements into account, such as the displacement of drug from the cyclodextrin cavity by bile salts present in the small intestine. As bile salts in the intestine are present at concentrations above the critical micelle concentration, an understanding of the interaction between cyclodextrins and bile salts at such supramicellar concentrations (SMC) is required for a better biopharmaceutical understanding of the release mechanism from orally dosed cyclodextrin complexes. To address this, experiments were conducted by isothermal titration calorimetry to determine how various β-cyclodextrins and bile salt interacts at SMC. Combined analysis of the current results and earlier data demonstrated that direct interactions between bile salt micelles and cyclodextrin were negligible. From this knowledge, an extended form of the UCD was suggested to describe the concentration of cyclodextrins to achieve full drug solubilization in the intestine where bile salts are present. Dosing cyclodextrins above this limit will diminish the free drug concentration, potentially decreasing the amount of drug absorbed. PMID:26502027

  5. Discovery of bile salt hydrolase inhibitors using an efficient high-throughput screening system.

    PubMed

    Smith, Katie; Zeng, Ximin; Lin, Jun

    2014-01-01

    The global trend of restricting the use of antibiotic growth promoters (AGP) in animal production necessitates the need to develop valid alternatives to maintain productivity and sustainability of food animals. Previous studies suggest inhibition of bile salt hydrolase (BSH), an intestinal bacteria-produced enzyme that exerts negative impact on host fat digestion and utilization, is a promising approach to promote animal growth performance. To achieve the long term goal of developing novel alternatives to AGPs, in this study, a rapid and convenient high-throughput screening (HTS) system was developed and successfully used for identification of BSH inhibitors. With the aid of a high-purity BSH from a chicken Lactobacillus salivarius strain, we optimized various screening conditions (e.g. BSH concentration, reaction buffer pH, incubation temperature and length, substrate type and concentration) and establish a precipitation-based screening approach to identify BSH inhibitors using 96-well or 384-well microplates. A pilot HTS was performed using a small compound library comprised of 2,240 biologically active and structurally diverse compounds. Among the 107 hits, several promising and potent BSH inhibitors (e.g. riboflavin and phenethyl caffeate) were selected and validated by standard BSH activity assay. Interestingly, the HTS also identified a panel of antibiotics as BSH inhibitor; in particular, various tetracycline antibiotics and roxarsone, the widely used AGP, have been demonstrated to display potent inhibitory effect on BSH. Together, this study developed an efficient HTS system and identified several BSH inhibitors with potential as alternatives to AGP. In addition, the findings from this study also suggest a new mode of action of AGP for promoting animal growth. PMID:24454844

  6. Discovery of Bile Salt Hydrolase Inhibitors Using an Efficient High-Throughput Screening System

    PubMed Central

    Smith, Katie; Zeng, Ximin; Lin, Jun

    2014-01-01

    The global trend of restricting the use of antibiotic growth promoters (AGP) in animal production necessitates the need to develop valid alternatives to maintain productivity and sustainability of food animals. Previous studies suggest inhibition of bile salt hydrolase (BSH), an intestinal bacteria-produced enzyme that exerts negative impact on host fat digestion and utilization, is a promising approach to promote animal growth performance. To achieve the long term goal of developing novel alternatives to AGPs, in this study, a rapid and convenient high-throughput screening (HTS) system was developed and successfully used for identification of BSH inhibitors. With the aid of a high-purity BSH from a chicken Lactobacillus salivarius strain, we optimized various screening conditions (e.g. BSH concentration, reaction buffer pH, incubation temperature and length, substrate type and concentration) and establish a precipitation-based screening approach to identify BSH inhibitors using 96-well or 384-well microplates. A pilot HTS was performed using a small compound library comprised of 2,240 biologically active and structurally diverse compounds. Among the 107 hits, several promising and potent BSH inhibitors (e.g. riboflavin and phenethyl caffeate) were selected and validated by standard BSH activity assay. Interestingly, the HTS also identified a panel of antibiotics as BSH inhibitor; in particular, various tetracycline antibiotics and roxarsone, the widely used AGP, have been demonstrated to display potent inhibitory effect on BSH. Together, this study developed an efficient HTS system and identified several BSH inhibitors with potential as alternatives to AGP. In addition, the findings from this study also suggest a new mode of action of AGP for promoting animal growth. PMID:24454844

  7. Ion pairing with bile salts modulates intestinal permeability and contributes to food-drug interaction of BCS class III compound trospium chloride.

    PubMed

    Heinen, Christian A; Reuss, Stefan; Amidon, Gordon L; Langguth, Peter

    2013-11-01

    In the current study the involvement of ion pair formation between bile salts and trospium chloride (TC), a positively charged Biopharmaceutical Classification System (BCS) class III substance, showing a decrease in bioavailability upon coadministration with food (negative food effect) was investigated. Isothermal titration calorimetry provided evidence of a reaction between TC and bile acids. An effect of ion pair formation on the apparent partition coefficient (APC) was examined using (3)H-trospium. The addition of bovine bile and bile extract porcine led to a significant increase of the APC. In vitro permeability studies of trospium were performed across Caco-2-monolayers and excised segments of rat jejunum in a modified Ussing chamber. The addition of bile acids led to an increase of trospium permeation across Caco-2-monolayers and rat excised segments by approximately a factor of 1.5. The addition of glycochenodeoxycholate (GCDC) was less effective than taurodeoxycholate (TDOC). In the presence of an olive oil emulsion, a complete extinction of the permeation increasing effects of bile salts was observed. Thus, although there are more bile acids in the intestine in the fed state compared to the fasted state, these are not able to form ion pairs with trospium in fed state, because they are involved in the emulsification of dietary fats. In conclusion, the formation of ion pairs between trospium and bile acids can partially explain its negative food effect. Our results are presumably transferable to other organic cations showing a negative food effect.

  8. Effects of human and porcine bile on the proteome of Helicobacter hepaticus

    PubMed Central

    2012-01-01

    Background Helicobacter hepaticus colonizes the intestine and liver of mice causing hepatobiliary disorders such as hepatitis and hepatocellular carcinoma, and has also been associated with inflammatory bowel disease in children. In its habitat, H. hepaticus must encounter bile which has potent antibacterial properties. To elucidate virulence and host-specific adaptation mechanisms of H. hepaticus modulated by human or porcine bile, a proteomic study of its response to the two types of bile was performed employing two-dimensional gel electrophoresis (2-DE) and mass spectrometry. Results The 2-DE and mass spectrometry analyses of the proteome revealed that 46 proteins of H. hepaticus were differentially expressed in human bile, 18 up-regulated and 28 down-regulated. In the case of porcine bile, 32 proteins were differentially expressed of which 19 were up-regulated, and 13 were down-regulated. Functional classifications revealed that identified proteins participated in various biological functions including stress response, energy metabolism, membrane stability, motility, virulence and colonization. Selected genes were analyzed by RT-PCR to provide internal validation for the proteomic data as well as provide insight into specific expressions of motility, colonization and virulence genes of H. hepaticus in response to human or porcine bile. Conclusions Overall, the data suggested that bile is an important factor that determines virulence, host adaptation, localization and colonization of specific niches within host environment. PMID:22533459

  9. Interaction of Bile Salts with β-Cyclodextrins Reveals Nonclassical Hydrophobic Effect and Enthalpy-Entropy Compensation.

    PubMed

    Paul, Bijan K; Ghosh, Narayani; Mukherjee, Saptarshi

    2016-04-28

    Herein, we present an endeavor toward exploring the lacuna underlying the host:guest chemistry of inclusion complex formation between bile salt(s) and β-cyclodextrin(s) (βCDs). An extensive thermodynamic investigation based on isothermal titration calorimetry (ITC) demonstrates a dominant contribution from exothermic enthalpy change (ΔH < 0) accompanying the phenomenon of inclusion complex formation, along with a relatively smaller contribution to total free energy change from the entropic component. However, the negative heat capacity change (ΔCp < 0) displays the hallmark for a pivotal role of hydrophobic effect underlying the interaction. Contrary to the classical hydrophobic effect, such apparently paradoxical thermodynamic signature has been adequately described under the notion of "nonclassical hydrophobic effect". On the basis of our results, the displacement of disordered water from hydrophobic binding sites has been argued to mark the enthalpic signature and the key role of such interaction forces is further corroborated from enthalpy-entropy compensation behavior showing indication for almost complete compensation. To this end, we have quantified the interaction of two bile salt molecules (namely, sodium deoxycholate and sodium glycocholate) with a series of varying chemical substituents on the host counterpart, namely, βCD, (2-hydroxypropyl)-βCD, and methyl βCD.

  10. Interaction of Bile Salts with β-Cyclodextrins Reveals Nonclassical Hydrophobic Effect and Enthalpy-Entropy Compensation.

    PubMed

    Paul, Bijan K; Ghosh, Narayani; Mukherjee, Saptarshi

    2016-04-28

    Herein, we present an endeavor toward exploring the lacuna underlying the host:guest chemistry of inclusion complex formation between bile salt(s) and β-cyclodextrin(s) (βCDs). An extensive thermodynamic investigation based on isothermal titration calorimetry (ITC) demonstrates a dominant contribution from exothermic enthalpy change (ΔH < 0) accompanying the phenomenon of inclusion complex formation, along with a relatively smaller contribution to total free energy change from the entropic component. However, the negative heat capacity change (ΔCp < 0) displays the hallmark for a pivotal role of hydrophobic effect underlying the interaction. Contrary to the classical hydrophobic effect, such apparently paradoxical thermodynamic signature has been adequately described under the notion of "nonclassical hydrophobic effect". On the basis of our results, the displacement of disordered water from hydrophobic binding sites has been argued to mark the enthalpic signature and the key role of such interaction forces is further corroborated from enthalpy-entropy compensation behavior showing indication for almost complete compensation. To this end, we have quantified the interaction of two bile salt molecules (namely, sodium deoxycholate and sodium glycocholate) with a series of varying chemical substituents on the host counterpart, namely, βCD, (2-hydroxypropyl)-βCD, and methyl βCD. PMID:27054266

  11. Identification and characterization of a bile salt hydrolase from Lactobacillus salivarius for development of novel alternatives to antibiotic growth promoters.

    PubMed

    Wang, Zhong; Zeng, Ximin; Mo, Yiming; Smith, Katie; Guo, Yuming; Lin, Jun

    2012-12-01

    Antibiotic growth promoters (AGPs) have been used as feed additives to improve average body weight gain and feed efficiency in food animals for more than 5 decades. However, there is a worldwide trend to limit AGP use to protect food safety and public health, which raises an urgent need to discover effective alternatives to AGPs. The growth-promoting effect of AGPs has been shown to be highly correlated with the decreased activity of intestinal bile salt hydrolase (BSH), an enzyme that is produced by various gut microflora and involved in host lipid metabolism. Thus, BSH inhibitors are likely promising feed additives to AGPs to improve animal growth performance. In this study, the genome of Lactobacillus salivarius NRRL B-30514, a BSH-producing strain isolated from chicken, was sequenced by a 454 GS FLX sequencer. A BSH gene identified by genome analysis was cloned and expressed in an Escherichia coli expression system for enzymatic analyses. The BSH displayed efficient hydrolysis activity for both glycoconjugated and tauroconjugated bile salts, with slightly higher catalytic efficiencies (k(cat)/K(m)) on glycoconjugated bile salts. The optimal pH and temperature for the BSH activity were 5.5 and 41°C, respectively. Examination of a panel of dietary compounds using the purified BSH identified some potent BSH inhibitors, in which copper and zinc have been recently demonstrated to promote feed digestion and body weight gain in different food animals. In sum, this study identified and characterized a BSH with broad substrate specificity from a chicken L. salivarius strain and established a solid platform for us to discover novel BSH inhibitors, the promising feed additives to replace AGPs for enhancing the productivity and sustainability of food animals. PMID:23064348

  12. Identification and characterization of a bile salt hydrolase from Lactobacillus salivarius for development of novel alternatives to antibiotic growth promoters.

    PubMed

    Wang, Zhong; Zeng, Ximin; Mo, Yiming; Smith, Katie; Guo, Yuming; Lin, Jun

    2012-12-01

    Antibiotic growth promoters (AGPs) have been used as feed additives to improve average body weight gain and feed efficiency in food animals for more than 5 decades. However, there is a worldwide trend to limit AGP use to protect food safety and public health, which raises an urgent need to discover effective alternatives to AGPs. The growth-promoting effect of AGPs has been shown to be highly correlated with the decreased activity of intestinal bile salt hydrolase (BSH), an enzyme that is produced by various gut microflora and involved in host lipid metabolism. Thus, BSH inhibitors are likely promising feed additives to AGPs to improve animal growth performance. In this study, the genome of Lactobacillus salivarius NRRL B-30514, a BSH-producing strain isolated from chicken, was sequenced by a 454 GS FLX sequencer. A BSH gene identified by genome analysis was cloned and expressed in an Escherichia coli expression system for enzymatic analyses. The BSH displayed efficient hydrolysis activity for both glycoconjugated and tauroconjugated bile salts, with slightly higher catalytic efficiencies (k(cat)/K(m)) on glycoconjugated bile salts. The optimal pH and temperature for the BSH activity were 5.5 and 41°C, respectively. Examination of a panel of dietary compounds using the purified BSH identified some potent BSH inhibitors, in which copper and zinc have been recently demonstrated to promote feed digestion and body weight gain in different food animals. In sum, this study identified and characterized a BSH with broad substrate specificity from a chicken L. salivarius strain and established a solid platform for us to discover novel BSH inhibitors, the promising feed additives to replace AGPs for enhancing the productivity and sustainability of food animals.

  13. In vitro model systems to investigate bile salt export pump (BSEP) activity and drug interactions: A review.

    PubMed

    Cheng, Yaofeng; Woolf, Thomas F; Gan, Jinping; He, Kan

    2016-08-01

    The bile salt export pump protein (BSEP), expressed on the canalicular membranes of hepatocytes, is primarily responsible for the biliary excretion of bile salts. The inhibition of BSEP transport activity can lead to an increase in intracellular bile salt levels and liver injury. This review discusses the various in vitro assays currently available for assessing the effect of drugs or other chemical entities to modulate BSEP transport activity. BSEP transporter assays use one of the following platforms: Xenopus laevis oocytes; canalicular membrane vesicles (CMV); BSEP-expressed membrane vesicles; cell lines expressing BSEP; sandwich cultured hepatocytes (SCH); and hepatocytes in suspension. Two of these, BSEP-expressed insect membrane vesicles and sandwich cultured hepatocytes, are the most commonly used assays. BSEP membrane vesicles prepared from transfected insect cells are useful for assessing BSEP inhibition or substrate specificity and exploring mechanisms of BSEP-associated genetic diseases. This model can be applied in a high-throughput format for discovery-drug screening. However, experimental results from use of membrane vesicles may lack physiological relevance and the model does not allow for investigation of in situ metabolism in modulation of BSEP activity. Hepatocyte-based assays that use the SCH format provide results that are generally more physiologically relevant than membrane assays. The SCH model is useful in detailed studies of the biliary excretion of drugs and BSEP inhibition, but due to the complexity of SCH preparation, this model is used primarily for determining biliary clearance and BSEP inhibition in a limited number of compounds. The newly developed hepatocyte in suspension assay avoids many of the complexities of the SCH method. The use of pooled cryopreserved hepatocytes in suspension minimizes genetic variance and individual differences in BSEP activity and also provides the opportunity for higher throughput screening and cross

  14. IS30-related transposon mediated insertional inactivation of bile salt hydrolase (bsh1) gene of Lactobacillus plantarum strain Lp20.

    PubMed

    Kumar, Rajesh; Grover, Sunita; Kaushik, Jai K; Batish, Virender Kumar

    2014-01-01

    Lactobacillus plantarum is a flexible and versatile microorganism that inhabits a variety of niches, and its genome may express up to four bsh genes to maximize its survival in the mammalian gut. However, the ecological significance of multiple bsh genes in L. plantarum is still not clearly understood. Hence, this study demonstrated the disruption of bile salt hydrolase (bsh1) gene due to the insertion of a transposable element in L. plantarum Lp20 - a wild strain of human fecal origin. Surprisingly, L. plantarum strain Lp20 produced a ∼2.0 kb bsh1 amplicon against the normal size (∼1.0 kb) bsh1 amplicon of Bsh(+)L. plantarum Lp21. Strain Lp20 exhibited minimal Bsh activity in spite of having intact bsh2, bsh3 and bsh4 genes in its genome and hence had a Bsh(-) phenotype. Cloning and sequence characterization of Lp20 bsh1 gene predicted four individual open reading frames (ORFs) within this region. BLAST analysis of ORF1 and ORF2 revealed significant sequence similarity to the L. plantarum bsh1 gene while ORF3 and ORF4 showed high sequence homology to IS30-family transposases. Since, IS30-related transposon element was inserted within Lp20 bsh1 gene in reverse orientation (3'-5'), it introduced several stop codons and disrupted the protein reading frames of both Bsh1 and transposase. Inverted terminal repeats (GGCAGATTG) of transposon, mediated its insertion at 255-263 nt and 1301-1309 nt positions of Lp20 bsh1 gene. In conclusion, insertion of IS30 related-transposon within the bsh1 gene sequence of L. plantarum strain Lp20 demolished the integrity and functionality of Bsh1 enzyme. Additionally, this transposon DNA sequence remains active among various Lactobacillus spp. and hence harbors the potential to be explored in the development of efficient insertion mutagenesis system.

  15. Dihydroxy bile salt-induced secretion of rubidium ion across the rabbit distal colon

    SciTech Connect

    Freel, R.W.

    1987-04-01

    Possible mechanisms of dihydroxy bile salt-induced K/sup +/ secretion by the mammalian colon were evaluated by studying the effects of taurochenodeoxycholate (TCDC) on /sup 86/Rb/sup +/ transport across the isolated, short-circuited rabbit distal colon. Simultaneous measurements of /sup 86/Rb/sup +/ and /sup 42/K/sup +/ unidirectional fluxes were highly correlated, indicating that Rb/sup +/ is a suitable tracer for K/sup +/ transport across the colon. Furthermore, mucosal Ba/sup 2 +/ (4 mM) or serosal ouabain (0.1 mM) decreased serosal to mucosal rubidium flux (J/sub s ..-->.. m//sup Rb/) without affecting J/sub m ..-->.. s//sup Rb/. Dibutyryl cyclic adenosine monophosphate (dBcAMP, 0.5 mM serosal) specifically increased J/sub s ..-->.. m//sup Rb of controls through a barium- (4 mM, mucosal) sensitive pathway without affecting J/sub s ..-->.. m//Rb/. Mucosal addition of 2 mM TCDC increased tissue conductance (G/sub T/), reduced short-circuit (I/sub sc/) slightly, and reversed J/sub net//sup Rb/ principally by increasing J/sub s ..-->.. m//sup Rb/. The TCDC-induced increases in J/sub s ..-->.. m//sup Rb/ were reduced by 0.1 mM serosal ouabain or 4 mM mucosal Ba/sup 2 +/. Pretreatment with the putative calcium-calmodulin antagonist trifluoperazine blocked dBcAMP- and TCDC-induced increases in J/sub s ..-->.. m//sup Rb/ but did not prevent changes in G/sub T/ or I/sub sc/ produced by either secretagogue. It is concluded that TCDC stimulates Rb/sup +/ or K/sup +/ secretion by primarily increasing the efflux of these ions across Ba/sup 2 +/-sensitive K/sup +/ channels in the apical membrane and that this increase in permeability may be mediated intracellularly by the calcium-calmodulin complex.

  16. Photoactive bile salts with critical micellar concentration in the micromolar range.

    PubMed

    Gomez-Mendoza, Miguel; Marin, M Luisa; Miranda, Miguel A

    2016-05-14

    The aggregation behavior of bile salts is strongly dependent on the number of hydroxyl groups. Thus, cholic acid (CA), with three hydroxyls, starts forming aggregates at 15 mM, while deoxycholic, chenodeoxycholic or ursodeoxycholic acids, with two hydroxyls, start aggregating at 5-10 mM; for lithocholic acid, with only one hydroxyl group, aggregation is observed at lower concentration (2-3 mM). Here, the singular self-assembling properties of dansyl and naproxen derivatives of CA (3β-Dns-CA and 3β-NPX-CA, respectively) have been demonstrated on the basis of their photoactive properties. Thus, the emission spectra of 3β-Dns-CA registered at increasing concentrations (25-140 μM) showed a remarkable non-linear enhancement in the emission intensity accompanied by a hypsochromic shift of the maximum and up to a three-fold increase in the singlet lifetime. The inflection point at around 50-70 μM pointed to the formation of unprecedented assemblies at such low concentrations. In the case of 3β-NPX-CA, when the NPX relative triplet lifetime was plotted against concentration, a marked increase (up to two-fold) was observed at 40-70 μM, indicating the formation of new 3β-NPX-CA assemblies at ca. 50 μM. Additional evidence supporting the formation of new 3β-Dns-CA or 3β-NPX-CA assemblies at 40-70 μM was obtained from singlet excited state quenching experiments using iodide. Moreover, to address the potential formation of hybrid assemblies, 1 : 1 mixtures of 3β-Dns-CA and 3β-NPX-CA (2-60 μM, total concentration) were subjected to steady-state fluorescence experiments, and their behavior was compared to that of the pure photoactive derivatives. A lower increase in the emission was observed for 3β-NPX-CA in the mixture, while a huge increase was experienced by 3β-Dns-CA in the same concentration range (up to 60 μM total). A partial intermolecular energy transfer from NPX to Dns, consistent with their reported singlet energies, was revealed, pointing to the

  17. Determination of bile salt critical micellization concentration on the road to drug discovery.

    PubMed

    Natalini, Benedetto; Sardella, Roccaldo; Gioiello, Antimo; Ianni, Federica; Di Michele, Alessandro; Marinozzi, Maura

    2014-01-01

    With the discovery of the bile acid (BA)-activated nuclear and membrane receptors, the role of BAs as signalling molecules in important paracrine and endocrine networks has been fully documented in the last decade. Besides regulating their own synthesis and transport, BAs have been demonstrated being involved in triggering the adaptive response to cholestasis and other insults to liver. More to the point, their recognized ability to control the general energy-related metabolism and inflammation processes has contributed to justify the renewed interest towards this class of amphiphilic steroidal compounds. All these evidences feed a continuing interest in the BA research aimed at designing and synthesizing new side chain- and body-modified derivatives endowed with improved biological and physico-chemical profiles, as well as with proper ADMET behaviour. In this context, the micellar aggregation of BAs, and the respective critical micellization concentration (CMC) value (determined on the BA sodium salt, BS), is considered a key parameter that needs to be determined in the preliminary phase of compound characterization, being implicated in cytotoxicity issues. An extraordinary variety of different analytical techniques and methods have been proposed along the years with the aim of better identifying the start of the self-aggregation process of BS monomers. The unicity of the physico-chemical nature of such class of compounds can be invoked to explain this unusual interest. Accordingly, a number of both invasive and non-invasive approaches have been developed along with a limited number of indirect chromatographic-based estimation strategies. Worth to be mentioned among the non-invasive determination methods are those based on potentiometry, freezing point depression, surface tension, nuclear magnetic resonance, viscosimetry, turbidimetry, microcalorimetry, refractometry, conductimetry, spectrophotometry, cholesterol solubilization, and monoglucuronide solubilization

  18. Determination of bile salt critical micellization concentration on the road to drug discovery.

    PubMed

    Natalini, Benedetto; Sardella, Roccaldo; Gioiello, Antimo; Ianni, Federica; Di Michele, Alessandro; Marinozzi, Maura

    2014-01-01

    With the discovery of the bile acid (BA)-activated nuclear and membrane receptors, the role of BAs as signalling molecules in important paracrine and endocrine networks has been fully documented in the last decade. Besides regulating their own synthesis and transport, BAs have been demonstrated being involved in triggering the adaptive response to cholestasis and other insults to liver. More to the point, their recognized ability to control the general energy-related metabolism and inflammation processes has contributed to justify the renewed interest towards this class of amphiphilic steroidal compounds. All these evidences feed a continuing interest in the BA research aimed at designing and synthesizing new side chain- and body-modified derivatives endowed with improved biological and physico-chemical profiles, as well as with proper ADMET behaviour. In this context, the micellar aggregation of BAs, and the respective critical micellization concentration (CMC) value (determined on the BA sodium salt, BS), is considered a key parameter that needs to be determined in the preliminary phase of compound characterization, being implicated in cytotoxicity issues. An extraordinary variety of different analytical techniques and methods have been proposed along the years with the aim of better identifying the start of the self-aggregation process of BS monomers. The unicity of the physico-chemical nature of such class of compounds can be invoked to explain this unusual interest. Accordingly, a number of both invasive and non-invasive approaches have been developed along with a limited number of indirect chromatographic-based estimation strategies. Worth to be mentioned among the non-invasive determination methods are those based on potentiometry, freezing point depression, surface tension, nuclear magnetic resonance, viscosimetry, turbidimetry, microcalorimetry, refractometry, conductimetry, spectrophotometry, cholesterol solubilization, and monoglucuronide solubilization

  19. Photoactive bile salts with critical micellar concentration in the micromolar range.

    PubMed

    Gomez-Mendoza, Miguel; Marin, M Luisa; Miranda, Miguel A

    2016-05-14

    The aggregation behavior of bile salts is strongly dependent on the number of hydroxyl groups. Thus, cholic acid (CA), with three hydroxyls, starts forming aggregates at 15 mM, while deoxycholic, chenodeoxycholic or ursodeoxycholic acids, with two hydroxyls, start aggregating at 5-10 mM; for lithocholic acid, with only one hydroxyl group, aggregation is observed at lower concentration (2-3 mM). Here, the singular self-assembling properties of dansyl and naproxen derivatives of CA (3β-Dns-CA and 3β-NPX-CA, respectively) have been demonstrated on the basis of their photoactive properties. Thus, the emission spectra of 3β-Dns-CA registered at increasing concentrations (25-140 μM) showed a remarkable non-linear enhancement in the emission intensity accompanied by a hypsochromic shift of the maximum and up to a three-fold increase in the singlet lifetime. The inflection point at around 50-70 μM pointed to the formation of unprecedented assemblies at such low concentrations. In the case of 3β-NPX-CA, when the NPX relative triplet lifetime was plotted against concentration, a marked increase (up to two-fold) was observed at 40-70 μM, indicating the formation of new 3β-NPX-CA assemblies at ca. 50 μM. Additional evidence supporting the formation of new 3β-Dns-CA or 3β-NPX-CA assemblies at 40-70 μM was obtained from singlet excited state quenching experiments using iodide. Moreover, to address the potential formation of hybrid assemblies, 1 : 1 mixtures of 3β-Dns-CA and 3β-NPX-CA (2-60 μM, total concentration) were subjected to steady-state fluorescence experiments, and their behavior was compared to that of the pure photoactive derivatives. A lower increase in the emission was observed for 3β-NPX-CA in the mixture, while a huge increase was experienced by 3β-Dns-CA in the same concentration range (up to 60 μM total). A partial intermolecular energy transfer from NPX to Dns, consistent with their reported singlet energies, was revealed, pointing to the

  20. Interaction of a dietary fiber (pectin) with gastrointestinal components (bile salts, calcium, and lipase): a calorimetry, electrophoresis, and turbidity study.

    PubMed

    Espinal-Ruiz, Mauricio; Parada-Alfonso, Fabián; Restrepo-Sánchez, Luz-Patricia; Narváez-Cuenca, Carlos-Eduardo; McClements, David Julian

    2014-12-31

    An in vitro gastrointestinal model consisting of oral, gastric, and intestinal phases was used to elucidate the impact of pectin on the digestion of emulsified lipids. Pectin reduced the extent of lipid digestion, which was attributed to its binding interactions with specific gastrointestinal components. The interaction of pectin with bile salts, lipase, CaCl2, and NaCl was therefore investigated by turbidity, microstructure, electrophoresis, and isothermal titration calorimetry (ITC) at pH 7.0 and 37 °C. ITC showed that the interaction of pectin was endothermic with bile salts, but exothermic with CaCl2, NaCl, and lipase. Electrophoresis, microstructure, and turbidity measurements showed that anionic pectin formed electrostatic complexes with calcium ions, which may have decreased lipid digestion due to increased lipid flocculation or microgel formation because this would reduce the surface area of lipid exposed to the lipase. This research provides valuable insights into the physicochemical and molecular mechanisms of the interaction of pectin with gastrointestinal components that may affect the rate and extent of lipid digestion.

  1. Impact of mucin, bile salts and cholesterol on the virulence of Vibrio anguillarum towards gnotobiotic sea bass (Dicentrarchus labrax) larvae.

    PubMed

    Li, Xuan; Bossier, Peter; Dierckens, Kristof; Laureau, Stanislas; Defoirdt, Tom

    2015-01-30

    In this study, we investigated the impact of the host factors mucin, bile salts and cholesterol on the virulence of the economically important aquatic pathogen Vibrio anguillarum towards sea bass larvae. Pretreatment of V. anguillarum with either one of the host factors (at 10 mg l(-1)) prior to inoculation into the sea bass rearing water increased virulence of the bacterium, although the effect of cholesterol was not significant. Each of the three host factors significantly increased several virulence-related phenotypes in V. anguillarum, i.e. protease activity, flagellar motility, biofilm formation and exopolysaccharide production, whereas there was no effect on growth of the bacterium under these conditions. Furthermore, the host factors increased the expression of genes involved in these phenotypes, i.e. the metalloprotease empA, the flagellar transcriptional regulator fleQ, the flagellin gene flaA, the chemotaxis methyltransferase gene cheR, the exopolysaccharide biosynthesis gene wbfD and the exopolysaccharide export gene wza. Our results indicate that V. anguillarum uses host mucin, bile salts, and cholesterol as cues to promote the expression of several important virulence traits that enhance the success of transmission from one host to another.

  2. Survival of O157:H7 and non-O157 serogroups of Escherichia coli in bovine rumen fluid and bile salts.

    PubMed

    Free, Angela L; Duoss, Heather A; Bergeron, Leeanne V; Shields-Menard, Sara A; Ward, Emily; Callaway, Todd R; Carroll, Jeffery A; Schmidt, Ty B; Donaldson, Janet R

    2012-11-01

    While Shiga toxin-producing Escherichia coli (STEC) reside asymptomatically within ruminants, particularly cattle, these strains pose a serious health risk to humans. Research related to STEC has historically focused upon O157:H7. However, with an increase in foodborne outbreaks of non-O157 origin and recent changes in testing for non-O157 by the U.S. Department of Agriculture Food Safety and Inspection Service (USDA-FSIS), there is now a critical need to understand the biological activity of non-O157 serogroups. The focus of this study was to determine whether variations exist in the ability of different serotypes of STEC to survive within bovine rumen fluid medium and bile salts. The results of this study demonstrated through viable plate count analysis that the five serotypes tested (O157:H7, O111:H8, O103:K.:H8, O145:H28, and O26:H11) were capable of growing in rumen fluid medium. However, the concentrations of the serotypes O103:K.:H8 and O26:H11 after 24 h were significantly less (p < 0.05) than that observed for the other serotypes tested. A significant decrease (p = 0.03) in the survival of O103:K.:H8 in 50 mg/mL of bovine bile salts in comparison to the other STEC strains tested was also observed. Collectively, these data suggest that non-O157 serogroups of E. coli respond differently to the environment of the bovine gastrointestinal tract. Further research is needed to elucidate how these differential physiological variations correlate with alterations in colonization success within ruminants and how they may impact human illnesses.

  3. Equilibrium and kinetic factors influencing bile sequestrant efficacy.

    PubMed

    Luner, P E; Amidon, G L

    1992-05-01

    In vitro bile salt binding equilibria and kinetic studies were performed with cholestyramine to determine how these factors influence bile sequestrant efficacy in vivo. Chloride ion at physiologic concentrations caused more than a twofold reduction in glycocholate (GCH) binding, compared to binding in the absence of salt, over a range of GCH concentrations and was also observed to displace bound GCH. In addition, chloride ion displaced from cholestyramine as a result of bile salt binding was measured using a chloride selective electrode, and the results show that bile salt binding is due to ion exchange. Comparison of the results of the equilibrium binding experiments to human data shows that the effect of anion binding competition alone cannot account for the lack of efficacy of cholestyramine. Consideration of other effects, such as additional binding competition or poor availability for binding, based on data from the literature, shows that adequate bile salt binding potential exists and that these interferences are not major factors influencing resin efficacy. In kinetic studies, both binding uptake of GCH and displacement of GCH from cholestyramine by chloride ion were relatively rapid, indicating that cholestyramine should equilibrate rapidly with bile salts in the GI tract. Based on these findings, it is suggested that the low efficacy of cholestyramine is a result mainly of its relatively poor ability to prevent bile salt reabsorption in the ileum.

  4. Adsorption of bile acid by chitosan salts prepared with cinnamic acid and analogue compounds.

    PubMed

    Murata, Yoshifumi; Nagaki, Kumiko; Kofuji, Kyouko; Sanae, Fujiko; Kontani, Hitoshi; Kawashima, Susumu

    2006-01-01

    A chitosan (CS) powder treated with cinnamic acid and an analogue compound (CN) was prepared as CS-CN. Using it, bile acid adsorption by CS-CN and the release of CN were investigated in vitro. When CS-CN was soaked in a taurocholate solution, it released CN and simultaneously adsorbed the bile acid. For CS-CN prepared with cinnamic acid, the amount of CN released was 0.286 +/- 0.001 mmol/g CS-CN; the amount of taurocholate adsorbed was 0.284 +/- 0.003 mmol/g CS-CN. These two functions were recognized on alginate or pectin gel beads containing CS-CN. The amount of released CN was altered extensively by the species of CN used for gel-bead preparation. Results suggest that CS-CN is a candidate for complementary medicine to prevent lifestyle-related diseases.

  5. Determination of conjugated bile acids in human bile and duodenal fluid by reverse-phase high-performance liquid chromatography.

    PubMed

    Bloch, C A; Watkins, J B

    1978-05-01

    A simple mehtod using reverse-phase liquid chromatography is presented for resolution and quantitation of the major conjugated bile acids of man, including the glycine and taurine conjugates of the dihydroxy bile acids, chenodeoxycholic and deoxycholic acid. Using modern, high-performance chromatographic equipment, analysis time is less than 30 minutes. The quantitative range of the method, with detection by refractive index, is 0.05 to 0.1 mumol of bile acid and the limit of detection for an injection sample is 0.01 mumol. This provides a sensitivity sufficient for analysis of dilute duodenal and gallbladder bile with minimal sample preparation.

  6. Effect of side chain length on bile acid conjugation: glucuronidation, sulfation and coenzyme A formation of nor-bile acids and their natural C24 homologs by human and rat liver fractions.

    PubMed

    Kirkpatrick, R B; Green, M D; Hagey, L R; Hofmann, A F; Tephly, T R

    1988-01-01

    The effect of side chain length on bile acid conjugation by human and rat liver fractions was examined. The rate of conjugation with glucuronic acid, sulfate and coenzyme A of several natural (C24) bile acids was compared with that of their corresponding nor-bile acids. The rate of coenzyme A ester formation by nor-bile acids was much lower than that of the natural bile acids. In human liver microsomes, the rate of coenzyme A formation was less than 8% of the rate for the corresponding C24 bile acid. Rat liver microsomes formed the coenzyme A ester of nor-bile acids less than 20% of the rate of their corresponding C24 homologs. Glucuronidation rates were greater than sulfation rates in both species. With human liver microsomes, nor-bile acids were glucuronidated more rapidly than their corresponding C24 homologs, whereas with rat liver microsomes the reverse was true. Purified 3 alpha-OH androgen UDP-glucuronyltransferase catalyzed the glucuronidation of both nor-bile acids and bile acids. Human liver cytosol sulfated nor-bile acids more slowly than the corresponding bile acids. Rat liver cytosol, however, sulfated nor-bile acids more rapidly than the corresponding bile acids. The highest rate was seen with lithocholylglycine. The results indicate that the novel biotransformation of nor-bile acids seen in vivo--sulfation and glucuronidation rather than amidation--is most likely explained as a consequent of defective amidation, to which the rate of coenzyme A formation contributes. Thus, side chain and nuclear structures as well as species differences in conjugating enzyme activity are determinants of the pattern of bile acid biotransformation by the mammalian liver.

  7. Bipolar and Related Disorders Induced by Sodium 4-Phenylbutyrate in a Male Adolescent with Bile Salt Export Pump Deficiency Disease

    PubMed Central

    Simonetti, Giulia; Pirillo, Martina; Taruschio, Gianfranco; Andreone, Pietro

    2016-01-01

    Bile Salt Export Pump (BSEP) Deficiency disease, including Progressive Familial Intrahepatic Cholestasis type 2 (PFIC2), is a rare disease, usually leading within the first ten years to portal hypertension, liver failure, hepatocellular carcinoma. Often liver transplantation is needed. Sodium 4-phenylbutyrate (4-PB) seems to be a potential therapeutic compound for PFIC2. Psychiatric side effects in the adolescent population are little known and little studied since the drug used to treat children and infants. So we described a case of Caucasian boy, suffering from a late onset PFIC2, listed for a liver transplant when he was sixteen and treated with 4-FB (200 mg per kilogram of body weight per day). The drug was discontinued for the onset of bipolar and related disorders. This case illustrates possible psychiatric side effects of the drug. PMID:27757140

  8. Effects of Bile Salt Sodium Glycodeoxycholate on the Self-Assembly of PEO-PPO-PEO Triblock Copolymer P123 in Aqueous Solution.

    PubMed

    Bayati, Solmaz; Galantini, Luciano; Knudsen, Kenneth D; Schillén, Karin

    2015-12-22

    A comprehensive experimental study on the interaction between the PEO-PPO-PEO block copolymer P123 (EO20PO68EO20) and the anionic bile salt sodium glycodeoxycholate (NaGDC) in water has been performed. The work was aimed at investigating the suitability of using P123 as bile salt sequestrant beside the fundamental aspects of PEO-PPO-PEO block copolymer-bile salt interactions. Various experimental techniques including dynamic and static light scattering, small-angle X-ray scattering, and differential scanning calorimetry (DSC) were employed in combination with electrophoretic mobility measurements. The system was investigated at a constant P123 concentration of 1.74 mM and with varying bile salt concentrations up to approximately 250 mM NaGDC (or a molar ratio n(NaGDC)/n(P123) = 144). In the mixed P123-NaGDC solutions, the endothermic process related to the self-assembly of P123 was observed to gradually decrease in enthalpy and shift to higher temperatures upon progressive addition of NaGDC. To explain this effect, the formation of NaGDC micelles carrying partly dehydrated P123 unimers was proposed and translated into a stoichiometric model, which was able to fit the experimental DSC data. In the mixtures at low molar ratios, NaGDC monomers associated with the P123 micelle forming a charged "P123 micelle-NaGDC" complex with a dehydrated PPO core. These complexes disintegrated upon increasing NaGDC concentration to form small "NaGDC-P123" complexes visualized as bile salt micelles including one or a few P123 copolymer chains.

  9. Bile Formation and Secretion

    PubMed Central

    Boyer, James L.

    2014-01-01

    Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (~1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions. PMID:23897680

  10. Bile-salt-stimulated lipase and mucins from milk of ‘secretor’ mothers inhibit the binding of Norwalk virus capsids to their carbohydrate ligands

    PubMed Central

    2005-01-01

    Breast-feeding-associated protection against calicivirus diarrhoea is associated with the presence of high levels of 2-linked oligosaccharides in mother's milk, and human calicivirus strains including the NV (Norwalk virus) use gut 2-linked fucosylated glycans as receptors, suggesting the presence of decoy receptors in milk. Our aim was to analyse the ability of human milk to inhibit the attachment of rNV VLPs (recombinant NV-like particles) to their carbohydrate ligands and to characterize potential inhibitors found in milk. Milk from women with the secretor phenotype was strongly inhibitory, unlike milk from women that are non-secretors, which is devoid of 2-linked fucosylated structures. At least two fractions in human milk acted as inhibitors for the NV capsid attachment. The first fraction corresponded to BSSL (bile-salt-stimulated lipase) and the second to associated mucins MUC1 and MUC4. These proteins present tandem repeat O-glycosylated sequences that should act as decoy receptors for the NV, depending on the combined mother/child secretor status. PMID:16266293

  11. New chitosan salt in gastro-resistant oral formulation could interfere with enteric bile salts emulsification of diet fats: preliminary laboratory observations and physiologic rationale.

    PubMed

    Fratter, Andrea; Frare, Carmen; Uras, Giovanni; Bonini, Mauro; Casari Bariani, Enrico; Ragazzo, Barbara; Gaballo, Paolo; Longobardi, Pasquale; Codemo, Carlo; Paoli, Antonio

    2014-06-01

    Chitosan (CH) is a polymer of glucosamine that is extracted from the shells of several sea fruits. It is well recognized as a nutritional supplement that is used to reduce body weight and blood lipid levels, but its clinical efficacy has not been clearly demonstrated. The true mechanism of action and physiological processes involved in these properties of CH are not yet understood or explained. The most accepted theories assume that CH reduces dietary fat absorption by trapping the fat in the gastric lumen. The very low pH of the gastric lumen induces CH jellification and, therefore, entrapment of the fats. This article describes the most plausible mechanism by which CH interferes with fat absorption in the first part of the enteric tract while interacting with cholic acids. We emphasize the weak points of the classic CH-containing formulations, which are unable to prove this theory. We also report preliminary experimental data of a new CH salt-containing formulation that is capable of effectively interfering with bile salt emulsification processes and, as a result, reducing dietary fat absorption.

  12. Redox modulation and human bile duct cancer inhibition by curcumin.

    PubMed

    Suphim, Bunliang; Prawan, Auemduan; Kukongviriyapan, Upa; Kongpetch, Sarinya; Buranrat, Benjaporn; Kukongviriyapan, Veerapol

    2010-01-01

    Curcumin, a major component from tumeric and well-known dietary spice, possesses various pharmacological effects. The cancer chemoprevention effect is suggested to act through its pro-oxidant property. The study was to clarify effects of curcumin on cholangiocarcinoma cells, a cancer of the bile duct that refractory to chemotherapeutic drugs. We examined time-course of oxidant formation in relation to antitumor and the adaptive antioxidant response of the cells. Curcumin induced antiproliferation and apoptosis in KKU-M214 CCA cells with concentration- and time- dependent manners. The antiproliferative effect of curcumin was observed at concentrations as low as 3 microM and was not necessarily associated with oxidative stress, while induction of apoptosis required significant production of superoxide anion, suppression of cellular redox and collapse of mitochondrial transmembrane potential. Western blot analysis showed a temporal relationship between the suppression of nuclear NF-kappaB with Bcl-XL protein levels. Up-regulation of p53 and Bax was associated with marked oxidative stress and apoptosis. Curcumin also induced Nrf2 protein expression with up-regulation of gamma-glutamylcysteine ligase mRNA and increased cellular antioxidant, glutathione. The study suggests that curcumin could be developed into an effective chemoprevention against CCA.

  13. Decreased hepatotoxic bile acid composition and altered synthesis in progressive human nonalcoholic fatty liver disease

    SciTech Connect

    Lake, April D.; Novak, Petr; Shipkova, Petia; Aranibar, Nelly; Robertson, Donald; Reily, Michael D.; Lu, Zhenqiang; Lehman-McKeeman, Lois D.; Cherrington, Nathan J.

    2013-04-15

    Bile acids (BAs) have many physiological roles and exhibit both toxic and protective influences within the liver. Alterations in the BA profile may be the result of disease induced liver injury. Nonalcoholic fatty liver disease (NAFLD) is a prevalent form of chronic liver disease characterized by the pathophysiological progression from simple steatosis to nonalcoholic steatohepatitis (NASH). The hypothesis of this study is that the ‘classical’ (neutral) and ‘alternative’ (acidic) BA synthesis pathways are altered together with hepatic BA composition during progression of human NAFLD. This study employed the use of transcriptomic and metabolomic assays to study the hepatic toxicologic BA profile in progressive human NAFLD. Individual human liver samples diagnosed as normal, steatosis, and NASH were utilized in the assays. The transcriptomic analysis of 70 BA genes revealed an enrichment of downregulated BA metabolism and transcription factor/receptor genes in livers diagnosed as NASH. Increased mRNA expression of BAAT and CYP7B1 was observed in contrast to decreased CYP8B1 expression in NASH samples. The BA metabolomic profile of NASH livers exhibited an increase in taurine together with elevated levels of conjugated BA species, taurocholic acid (TCA) and taurodeoxycholic acid (TDCA). Conversely, cholic acid (CA) and glycodeoxycholic acid (GDCA) were decreased in NASH liver. These findings reveal a potential shift toward the alternative pathway of BA synthesis during NASH, mediated by increased mRNA and protein expression of CYP7B1. Overall, the transcriptomic changes of BA synthesis pathway enzymes together with altered hepatic BA composition signify an attempt by the liver to reduce hepatotoxicity during disease progression to NASH. - Highlights: ► Altered hepatic bile acid composition is observed in progressive NAFLD. ► Bile acid synthesis enzymes are transcriptionally altered in NASH livers. ► Increased levels of taurine and conjugated bile acids

  14. Enhanced Permeation of an Antiemetic Drug from Buccoadhesive Tablets by Using Bile Salts as Permeation Enhancers: Formulation Characterization, In Vitro, and Ex Vivo Studies

    PubMed Central

    Jain, C. P.; Joshi, Garima; Kataria, Udichi; Patel, Komal

    2016-01-01

    Buccal bioadhesive bilayer tablets of prochlorperazine maleate were designed and formulated by using buccoadhesive polymers such as hydroxypropylmethyl cellulose, Carbopol 934P, and sodium alginate. Physicochemical characteristics like the uniformity of weight, hardness, thickness, surface pH, drug content, swelling index, microenvironment pH, in vitro drug release, and in vivo buccoadhesion time of the prepared tablets were found to be dependent on the type and composition of the buccoadhesive materials used. The effect of bile salts on the permeation was studied through porcine buccal mucosa and it was found that out of three bile salts incorporated (sodium glycholate, sodium taurocholate, and sodium deoxycholate), sodium glycholate enhanced the permeation rate of prochlorperazine maleate by an enhancement factor of 1.37. PMID:27222611

  15. Transmembrane domain II of the human bile acid transporter SLC10A2 coordinates sodium translocation.

    PubMed

    Sabit, Hairat; Mallajosyula, Sairam S; MacKerell, Alexander D; Swaan, Peter W

    2013-11-01

    Human apical sodium-dependent bile acid transporter (hASBT, SLC10A2) is responsible for intestinal reabsorption of bile acids and plays a key role in cholesterol homeostasis. We used a targeted and systematic approach to delineate the role of highly conserved transmembrane helix 2 on the expression and function of hASBT. Cysteine mutation significantly depressed transport activity for >60% of mutants without affecting cell surface localization of the transporter. All mutants were inaccessible toward chemical modification by membrane-impermeant MTSET reagent, strongly suggesting that transmembrane 2 (TM2) plays an indirect role in bile acid substrate translocation. Both bile acid uptake and sodium dependence of TM2 mutants revealed a distinct α-helical periodicity. Kinetic studies with conservative and non-conservative mutants of sodium sensitive residues further underscored the importance of Gln(75), Phe(76), Met(79), Gly(83), Leu(86), Phe(90), and Asp(91) in hASBT function. Computational analysis indicated that Asp(91) may coordinate with sodium during the transport cycle. Combined, our data propose that a consortium of sodium-sensitive residues along with previously reported residues (Thr(134), Leu(138), and Thr(149)) from TM3 may form the sodium binding and translocation pathway. Notably, residues Gln(75), Met(79), Thr(82), and Leu(86) from TM2 are highly conserved in TM3 of a putative remote bacterial homologue (ASBTNM), suggesting a universal mechanism for the SLC10A transporter family.

  16. Determination of thermodynamic potentials and the aggregation number for micelles with the mass-action model by isothermal titration calorimetry: A case study on bile salts.

    PubMed

    Olesen, Niels Erik; Westh, Peter; Holm, René

    2015-09-01

    The aggregation number (n), thermodynamic potentials (ΔG, ΔH, ΔS) and critical micelle concentration (CMC) for 6 natural bile salts were determined on the basis of both original and previously published isothermal titration calorimetry (ITC) data. Different procedures to estimate parameters of micelles with ITC were compared to a mass-action model (MAM) of reaction type: n⋅S⇌Mn. This analysis can provide guidelines for future ITC studies of systems behaving in accordance with this model such as micelles and proteins that undergo self-association to oligomers. Micelles with small aggregation numbers, as those of bile salts, are interesting because such small aggregates cannot be characterized as a separate macroscopic phase and the widely applied pseudo-phase model (PPM) is inaccurate. In the present work it was demonstrated that the aggregation number of micelles was constant at low concentrations enabling determination of the thermodynamic potentials by the MAM. A correlation between the aggregation number and the heat capacity was found, which implies that the dehydrated surface area of bile salts increases with the aggregation number. This is in accordance with Tanford's principles of opposing forces where neighbouring molecules in the aggregate are better able to shield from the surrounding hydrophilic environment when the aggregation number increases.

  17. Codon and Propeptide Optimizations to Improve the Food-grade Expression of Bile Salt Hydrolase in Lactococcus lactis.

    PubMed

    Dong, Zixing; Zhang, Juan; Li, Huazhong; Du, Guocheng; Chen, Jian; Lee, Byonghoon

    2015-01-01

    To achieve the food-grade expression of bile salt hydrolase (BSH, EC 3.5.1.24) from Lactobacillus plantarum BBE7, the nisin controlled gene expression system (NICE), food-grade selection maker and signal peptide of Lactococcus lactis were used in this study. The open reading frame of BSH was optimized based on the codon bias of L. lactis, resulting in 12-fold and 9.5% increases in the intracellular and extracellular BSH activities, respectively. Three synthetic propeptides, LEISSTCDA (acidic), LGISSTCNA (neutral) and LKISSTCHA (basic) were also fused with signal peptide SPusp45 of vector pNZ8112 and introduced into the food-grade expression vector pNZ8149, respectively. Among these propeptides, acidic propeptide was effective in increasing the secretion efficiency and yield of BSH in recombinant bacteria, while neutral propeptide had no significant effect on the secretion of BSH. In contrast, basic propeptide strongly reduced the extracellular expression of BSH. By using codon optimization and the acidic propeptide together, the extracellular BSH activity was increased by 11.3%, reaching its maximum of 3.56 U/mg. To the best of our knowledge, this is the first report on the intracellular and extracellular expression of BSH using food-grade expression system, which would lay a solid foundation for large-scale production of BSH and other heterologous proteins in L. lactis. PMID:26059800

  18.  Bile salt export pump deficiency disease: two novel, late onset, ABCB11 mutations identified by next generation sequencing.

    PubMed

    Vitale, Giovanni; Pirillo, Martina; Mantovani, Vilma; Marasco, Elena; Aquilano, Adelia; Gamal, Nesrine; Francalanci, Paola; Conti, Fabio; Andreone, Pietro

    2016-01-01

     Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of autosomal recessive cholestatic diseases of childhood and represents the main indication for liver transplantation at this age; PFIC2 involves ABCB11 gene, that encodes the ATPdependent canalicular bile salt export pump (BSEP). Benign intrahepatic cholestasis (BRIC) identifies a group of diseases involving the same genes and characterized by intermittent attacks of cholestasis with no progression to liver cirrhosis. Diagnosis with standard sequencing techniques is expensive and available only at a few tertiary centers. We report the application of next generation sequencing (NGS) in the diagnosis of the familial intrahepatic cholestasis with a parallel sequencing of three causative genes. We identified the molecular defects in ABCB11 gene in two different probands who developed a severe cholestatic disease of unknown origin. In the first patient a compound heterozygosity for the novel frameshift mutation p.Ser1100GlnfsX38 and the missense variant p.Glu135Lys was detected. In the second patient, triggered by contraceptive therapy, we identified homozygosity for a novel missense variant p.Ala523Gly. In conclusion, these mutations seem to have a late onset and a less aggressive clinical impact, acting as an intermediate form between BRIC and PFIC. PMID:27493120

  19. Fluorescence probe studies of mixed micellar and lyotropic phases formed between an anionic bile salt and a cationic detergent

    SciTech Connect

    Wu, K.; McGown, L.B. )

    1994-01-27

    Fluorescent probes, including pyrene, benzo[ghi]perylene (BgP), and perylene, were used to study organized media formed between the anionic trihydroxy bile salt sodium taurocholate (NaTC) and the cationic detergent octyltrimethylammonium bromide (CTAB), over a wide concentration range that includes micellar and lyotropic phases. Solutions of the individual amphiphiles were studied as well. The location of a probe in the mixed micelles was found to depend on the solubility and size of the probe. The microenvironment of pyrene is dominated by NaTC in the mixed micelles, whereas the larger and less soluble perylene and BgP probes interact more favorably with the hydrophobic tails of the CTAB molecules. The photophysical responses of the probes reflect their different locations, providing different perspectives on the transitions in micellar structure. Bromide counterion at the micellar surfaces was found to be an important factor in the photophysical responses, along with accessibility to bulk solution. A scheme for mixed micellization is proposed that extends from large excesses of one amphiphile to large excesses of the other, over a wide range of total amphiphile concentration. Interestingly, the lyotropic phases formed between NaTC and CTAB have high bulk viscosity, but the probe microenvironment is less viscous than in the mixed micellar phases. 43 refs., 9 figs., 2 tabs.

  20. Effective mucoadhesive water-soluble polymers for the solidification transformation of phospholipid-bile salts-mixed micelles.

    PubMed

    Lv, Qingyuan; Li, Xianyi; Li, Ruisheng; Shen, Baode; Xu, He; Shen, Chengying; Dai, Ling; Han, Jin; Yuan, Hailong

    2014-11-01

    Cucurbitacin B (Cu B), formulated in the phospholipid-bile salts-mixed micelles (PL-BS-MMs), was transformed into dry powders by solidification process. Solidification methods for this transformation included freeze-drying, spray-drying or vacuum-drying, and different grades of process parameters called conservative, moderate and aggressive have been used in each solidification method, respectively. Saccharides (mannose, trehalose and glucose), polyethylene glycol (PEG) and mucoadhesive water-soluble polymers (carrageenan, hydroxpropylmethylcellulose (HPMC) and gelatin) were selected as the stabilizer, respectively. The influence of different stabilizers on the redispersibility of solid Cu B-PL/SDC-MMs was systemically investigated, such as the redispersibility index (RDI). The results showed that there were significant differences in RDI from samples stabilized by different stabilizers. The solid Cu B-PL/SDC-MMs stabilized by mucoadhesive water-soluble polymers (carrageenan, HPMC and gelatin) have better redispersibility under different solidification approaches, compared with those samples stabilized by other stabilizers. The results indicated that the mucoadhesive water-soluble polymers could effectively counter various stresses from the solidification process and prevent the nanocrystal surface from agglomeration. The combined action between steric hindrance and increased viscosity appeared to effectively avoid irreversible particle aggregation. PMID:25985572

  1. Analysis of Bile Acids

    NASA Astrophysics Data System (ADS)

    Sjövall, Jan; Griffiths, William J.; Setchell, Kenneth D. R.; Mano, Nariyasu; Goto, Junichi

    Bile acids constitute a large family of steroids in vertebrates, normally formed from cholesterol and carrying a carboxyl group in a side-chain of variable length. Bile alcohols, also formed from cholesterol, have similar structures as bile acids, except for the absence of a carboxyl group in the steroid skeleton. The conversion of cholesterol to bile acids and/or bile alcohols is of major importance for maintenance of cholesterol homeostasis, both from quantitative and regulatory points of view (Chiang, 2004; Kalaany and Mangelsdorf, 2006; Moore, Kato, Xie, et al., 2006; Scotti, Gilardi, Godio, et al., 2007). Appropriately conjugated bile acids and bile alcohols (also referred to as bile salts) are secreted in bile and serve vital functions in the absorption of lipids and lipid-soluble compounds (Hofmann, 2007). Reliable analytical methods are required for studies of the functions and pathophysiological importance of the variety of bile acids and bile alcohols present in living organisms. When combined with genetic and proteomic studies, analysis of these small molecules (in today's terminology: metabolomics, steroidomics, sterolomics, cholanoidomics, etc.) will lead to a deeper understanding of the integrated metabolic processes in lipid metabolism.

  2. A Bile Salt Hydrolase of Brucella abortus Contributes to the Establishment of a Successful Infection through the Oral Route in Mice▿ †

    PubMed Central

    Delpino, M. Victoria; Marchesini, María I.; Estein, Silvia M.; Comerci, Diego J.; Cassataro, Juliana; Fossati, Carlos A.; Baldi, Pablo C.

    2007-01-01

    Choloylglycine hydrolase (CGH), a bile salt hydrolase, has been annotated in all the available genomes of Brucella species. We obtained the Brucella CGH in recombinant form and demonstrated in vitro its capacity to cleave glycocholate into glycine and cholate. Brucella abortus 2308 (wild type) and its isogenic Δcgh deletion mutant exhibited similar growth rates in tryptic soy broth in the absence of bile. In contrast, the growth of the Δcgh mutant was notably impaired by both 5% and 10% bile. The bile resistance of the complemented mutant was similar to that of the wild-type strain. In mice infected through the intragastric or the intraperitoneal route, splenic infection was significantly lower at 10 and 20 days postinfection in animals infected with the Δcgh mutant than in those infected with the wild-type strain. For both routes, no differences in spleen CFU were found between animals infected with the wild-type strain and those infected with the complemented mutant. Mice immunized intragastrically with recombinant CGH mixed with cholera toxin (CGH+CT) developed a specific mucosal humoral (immunoglobulin G [IgG] and IgA) and cellular (interleukin-2) immune responses. Fifteen days after challenge by the same route with live B. abortus 2308 cells, splenic CFU counts were 10-fold lower in mice immunized with CGH+CT than in mice immunized with CT or phosphate-buffered saline. This study shows that CGH confers on Brucella the ability to resist the antimicrobial action of bile salts. The results also suggest that CGH may contribute to the ability of Brucella to infect the host through the oral route. PMID:17088355

  3. Characterization of AQPs in Mouse, Rat, and Human Colon and Their Selective Regulation by Bile Acids

    PubMed Central

    Yde, Jonathan; Keely, Stephen; Wu, Qi; Borg, Johan F.; Lajczak, Natalia; O’Dwyer, Aoife; Dalsgaard, Peter; Fenton, Robert A.; Moeller, Hanne B.

    2016-01-01

    In normal individuals, the epithelium of the colon absorbs 1.5–2 l of water a day to generate dehydrated feces. However, in the condition of bile acid malabsorption (BAM), an excess of bile acids in the colon results in diarrhea. Several studies have attempted to address the mechanisms contributing to BAM induced by various bile acids. However, none have addressed a potential dysregulation of aquaporin (AQP) water channels, which are responsible for the majority of transcellular water transport in epithelial cells, as a contributing factor to the onset of diarrhea and the pathogenesis of BAM. In this study, we aimed to systematically analyze the expression of AQPs in colonic epithelia from rat, mouse, and human and determine whether their expression is altered in a rat model of BAM. Mass spectrometry-based proteomics, RT-PCR, and western blotting identified various AQPs in isolated colonic epithelial cells from rats (AQP1, 3, 4, 7, 8) and mice (AQP1, 4, 8). Several AQPs were also detected in human colon (AQP1, 3, 4, 7–9). Immunohistochemistry localized AQP1 to the apical plasma membrane of epithelial cells in the bottom of the crypts, whereas AQP3 (rat, human) and AQP4 (mice, human) were localized predominantly in the basolateral plasma membrane. AQP8 was localized intracellularly and at the apical plasma membrane of epithelial cells. Rats fed sodium cholate for 72 h had significantly increased fecal water content, suggesting development of BAM-associated diarrhea. Colonic epithelial cells isolated from this model had significantly altered levels of AQP3, 7, and 8, suggesting that these AQPs may be involved in the pathogenesis of bile acid-induced diarrhea. PMID:27777930

  4. Activation of the Human Epithelial Sodium Channel (ENaC) by Bile Acids Involves the Degenerin Site.

    PubMed

    Ilyaskin, Alexandr V; Diakov, Alexei; Korbmacher, Christoph; Haerteis, Silke

    2016-09-16

    The epithelial sodium channel (ENaC) is a member of the ENaC/degenerin ion channel family, which also includes the bile acid-sensitive ion channel (BASIC). So far little is known about the effects of bile acids on ENaC function. ENaC is probably a heterotrimer consisting of three well characterized subunits (αβγ). In humans, but not in mice and rats, an additional δ-subunit exists. The aim of this study was to investigate the effects of chenodeoxycholic, cholic, and deoxycholic acid in unconjugated (CDCA, CA, and DCA) and tauro-conjugated (t-CDCA, t-CA, t-DCA) form on human ENaC in its αβγ- and δβγ-configuration. We demonstrated that tauro-conjugated bile acids significantly stimulate ENaC in the αβγ- and in the δβγ-configuration. In contrast, non-conjugated bile acids have a robust stimulatory effect only on δβγENaC. Bile acids stimulate ENaC-mediated currents by increasing the open probability of active channels without recruiting additional near-silent channels known to be activated by proteases. Stimulation of ENaC activity by bile acids is accompanied by a significant reduction of the single-channel current amplitude, indicating an interaction of bile acids with a region close to the channel pore. Analysis of the known ASIC1 (acid-sensing ion channel) crystal structure suggested that bile acids may bind to the pore region at the degenerin site of ENaC. Substitution of a single amino acid residue within the degenerin region of βENaC (N521C or N521A) significantly reduced the stimulatory effect of bile acids on ENaC, suggesting that this site is critical for the functional interaction of bile acids with the channel. PMID:27489102

  5. Na+/Taurocholate Cotransporting Polypeptide and Apical Sodium-Dependent Bile Acid Transporter Are Involved in the Disposition of Perfluoroalkyl Sulfonates in Humans and Rats

    PubMed Central

    Zhao, Wen; Zitzow, Jeremiah D.; Ehresman, David J.; Chang, Shu-Ching; Butenhoff, John L.; Forster, Jameson; Hagenbuch, Bruno

    2015-01-01

    Among the perfluoroalkyl sulfonates (PFASs), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS) have half-lives of several years in humans, mainly due to slow renal clearance and potential hepatic accumulation. Both compounds undergo enterohepatic circulation. To determine whether transporters involved in the enterohepatic circulation of bile acids are also involved in the disposition of PFASs, uptake of perfluorobutane sulfonate (PFBS), PFHxS, and PFOS was measured using freshly isolated human and rat hepatocytes in the absence or presence of sodium. The results demonstrated sodium-dependent uptake for all 3 PFASs. Given that the Na+/taurocholate cotransporting polypeptide (NTCP) and the apical sodium-dependent bile salt transporter (ASBT) are essential for the enterohepatic circulation of bile acids, transport of PFASs was investigated in stable CHO Flp-In cells for human NTCP or HEK293 cells transiently expressing rat NTCP, human ASBT, and rat ASBT. The results demonstrated that both human and rat NTCP can transport PFBS, PFHxS, and PFOS. Kinetics with human NTCP revealed Km values of 39.6, 112, and 130 µM for PFBS, PFHxS, and PFOS, respectively. For rat NTCP Km values were 76.2 and 294 µM for PFBS and PFHxS, respectively. Only PFOS was transported by human ASBT whereas rat ASBT did not transport any of the tested PFASs. Human OSTα/β was also able to transport all 3 PFASs. In conclusion, these results suggest that the long half-live and the hepatic accumulation of PFOS in humans are at least, in part, due to transport by NTCP and ASBT. PMID:26001962

  6. Image-guided intervention in the human bile duct using scanning fiber endoscope system

    NASA Astrophysics Data System (ADS)

    Seibel, Eric J.; Jo, Javier A.; Melville, C. David; Johnston, Richard S.; Naumann, Christopher R.; Saunders, Michael D.

    2012-01-01

    Bile duct cancers are increasing in frequency while being difficult to diagnose. Currently available endoscopic imaging devices used in the biliary tree are low resolution with poor image quality, leading to inadequate evaluation of indeterminate biliary strictures. However, a new ultrathin and flexible cholangioscope system has been successfully demonstrated in a human subject. This mini-cholangioscope system uses a scanning fiber endoscope (SFE) as a forward-imaging guidewire, dimensions of 1.2-mm diameter and 3-m length. Full color video (500-line resolution at 30Hz) is the standard SFE imaging mode using spiral scanning of red, green, and blue laser light at low power. Image-guided operation of the biopsy forceps was demonstrated in healthy human bile ducts with and without saline flushing. The laser-based video imaging can be switched to various modes to enhance tissue markers of disease, such as widefield fluorescence and enhanced spectral imaging. In parallel work, biochemical discrimination of tissue health in pig bile duct has been accomplished using fiberoptic delivery of pulsed UV illumination and time-resolved autofluorescence spectroscopic measurements. Implementation of time-resolved fluorescence spectroscopy for biochemical assessment of the bile duct wall is being done through a secondary endoscopic channel. Preliminary results indicate that adequate SNR levels (> 30 dB) can be achieved through a 50 micron fiber, which could serve as an optical biopsy probe. The SFE is an ideal mini-cholangioscope for integration of both tissue and molecular specific image contrast in the future. This will provide the physician with unprecedented abilities to target biopsy locations and perform endoscopically-guided therapies.

  7. Interaction of Bile Salts with Model Membranes Mimicking the Gastrointestinal Epithelium: A Study by Isothermal Titration Calorimetry.

    PubMed

    Coreta-Gomes, Filipe M; Martins, Patrícia A T; Velazquez-Campoy, Adrián; Vaz, Winchil L C; Geraldes, Carlos F G; Moreno, Maria João

    2015-08-25

    Bile salts (BS) are biosurfactants synthesized in the liver and secreted into the intestinal lumen where they solubilize cholesterol and other hydrophobic compounds facilitating their gastrointestinal absorption. Partition of BS toward biomembranes is an important step in both processes. Depending on the loading of the secreted BS micelles with endogeneous cholesterol and on the amount of cholesterol from diet, this may lead to the excretion or absorption of cholesterol, from cholesterol-saturated membranes in the liver or to gastrointestinal membranes, respectively. The partition of BS toward the gastrointestinal membranes may also affect the barrier properties of those membranes affecting the permeability for hydrophobic and amphiphilic compounds. Two important parameters in the interaction of the distinct BS with biomembranes are their partition coefficient and the rate of diffusion through the membrane. Altogether, they allow the calculation of BS local concentrations in the membrane as well as their asymmetry in both membrane leaflets. The local concentration and, most importantly, its asymmetric distribution in the bilayer are a measure of induced membrane perturbation, which is expected to significantly affect its properties as a cholesterol donor and hydrophobic barrier. In this work we have characterized the partition of several BS, nonconjugated and conjugated with glycine, to large unilamellar vesicles (LUVs) in the liquid-disordered phase and with liquid-ordered/liquid-disordered phase coexistence, using isothermal titration calorimetry (ITC). The partition into the liquid-disordered bilayer was characterized by large partition coefficients and favored by enthalpy, while association with the more ordered membrane was weak and driven only by the hydrophobic effect. The trihydroxy BS partitions less efficiently toward the membranes but shows faster translocation rates, in agreement with a membrane protective effect of those BS. The rate of translocation

  8. Chronic effect of oral cholestyramine, a bile salt sequestrant, and exogenous cholecystokinin on insulin release in rats.

    PubMed

    Kogire, M; Gomez, G; Uchida, T; Ishizuka, J; Greeley, G H; Thompson, J C

    1992-01-01

    Oral cholestyramine, a bile salt sequestrant, stimulates pancreatic exocrine secretion and growth chiefly by increasing cholecystokinin (CCK) release. In this report, we examine pancreatic insulin content and insulin release from the isolated perfused pancreas in rats given oral cholestyramine (4%, wt/wt) or subcutaneous CCK-8 (1 micrograms/kg every 8 h) for 2 weeks. Cholestyramine significantly increased pancreatic weight by 32%. CCK administration significantly increased pancreatic weight by 15%. Total pancreatic content of protein and DNA were also increased significantly by cholestyramine and pancreatic protein content was increased significantly by CCK administration. Total pancreatic insulin content was not affected by cholestyramine or CCK. Both cholestyramine and CCK significantly increased the first phase of glucose (8.4 mM)-stimulated release of insulin [mean insulin output (ng/min): control, 2.0 +/- 0.1; cholestyramine, 2.7 +/- 0.2; CCK, 2.6 +/- 0.2]. Cholestyramine also significantly enhanced the second phase of glucose-stimulated release of insulin. Insulin release stimulated by CCK-8 (10(-10) M) was not affected by oral cholestyramine or CCK treatment. These findings indicate that oral cholestyramine and exogenous CCK have a stimulatory effect on beta cell function. Since pancreatic insulin content was not affected by cholestyramine and CCK treatment, cholestyramine and CCK may increase the sensitivity of beta cells to glucose. The absence of a stimulatory effect of cholestyramine and CCK administration on insulin release in response to CCK-8 may be related to a down-regulation of CCK receptors on beta cells.

  9. Mucoadhesive buccal films containing phospholipid-bile salts-mixed micelles as an effective carrier for Cucurbitacin B delivery.

    PubMed

    Lv, Qingyuan; Shen, Chengying; Li, Xianyi; Shen, Baode; Yu, Chao; Xu, Pinghua; Xu, He; Han, Jin; Yuan, Hailong

    2015-05-01

    Cucurbitacin B (Cu B), a potent anti-cancer agent, suffers with the problems of water-insoluble, gastrointestinal side effects and non-specific toxicity via oral administration and drawbacks in patient's compliance and acceptance through injections. An integration of nanoscale carriers with mucoadhesive buccal films drug delivery system would resolve these issues effectively with greater therapeutic benefits and clinical significance. Thus, the drug loaded mucoadhesive buccal film was developed and characterized in this study and the carboxymethyl chitosan (CCS) was chosen as a bioadhesive polymer, glycerol was chosen as a plasticizer and phospholipid-bile salts-mixed micelles (PL-BS-MMs) was selected as the nanoscale carriers. The CCS-films containing Cu B loaded PL-SDC-MMs was evaluated for the mechanical properties, mucoadhesion properties, in vitro water-uptake, in vitro release and morphological properties, respectively. The optimal CCS-films containing Cu B loaded PL-SDC-MMs was easily reconstituted in a transparent and clear solution with spherical micelles in the submicron range. The in vivo study revealed a greater and more extended release of Cu B from nanoscale CCS-films compared to that from a conventional CCS films (C-CCS-films) and oral marketed tablet (Hulusupian). The absorption of Cu B from CCS-films containing Cu B loaded PL-SDC-MMs resulted in 2.69-fold increased in bioavailability as compared to conventional tablet formulation and 10.46 times with reference to the C-CCS-films formulation. Thus, this kind of mucoadhesive buccal film might be an alternative safe route for delivery of Cu B with better patient compliance and higher bioavailability for the treatments.

  10. Bile acid transporters

    PubMed Central

    Dawson, Paul A.; Lan, Tian; Rao, Anuradha

    2009-01-01

    In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na+ taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OSTα-OSTβ. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers. PMID:19498215

  11. E297G mutated bile salt export pump (BSEP) function enhancers derived from GW4064: structural development study and separation from farnesoid X receptor-agonistic activity.

    PubMed

    Misawa, Takashi; Hayashi, Hisamitsu; Makishima, Makoto; Sugiyama, Yuichi; Hashimoto, Yuichi

    2012-06-15

    Bile salt export pump (BSEP) is a member of the ATP-binding cassette transmembrane transporter family and mediates biliary excretion of bile acids from hepatocytes. Several BSEP mutants, including Glu297Gly (E297G) and Asp482Gly (D482G), cause progressive familial intrahepatic cholestasis type 2. We previously found that compounds based on GW4064, a representative farnesoid X receptor (FXR) agonist, enhanced E297G BSEP transport activity. Here, we conducted a structure-activity relationship analysis of GW4064 derivatives aimed at separating E297G BSEP-function-promoting activity and FXR-agonistic activity. Among newly synthesized reversed-amide derivatives of previously reported GW4064 analogs 2a-2f, we identified 7c as a selective BSEP function enhancer.

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

    PubMed Central

    Marschall, H U; Matern, H; Wietholtz, H; Egestad, B; Matern, S; Sjövall, J

    1992-01-01

    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. PMID:1602004

  13. Enhanced oral bioavailability of silymarin using liposomes containing a bile salt: preparation by supercritical fluid technology and evaluation in vitro and in vivo

    PubMed Central

    Yang, Gang; Zhao, Yaping; Zhang, Yongtai; Dang, Beilei; Liu, Ying; Feng, Nianping

    2015-01-01

    The aim of this investigation was to develop a procedure to improve the dissolution and bioavailability of silymarin (SM) by using bile salt-containing liposomes that were prepared by supercritical fluid technology (ie, solution-enhanced dispersion by supercritical fluids [SEDS]). The process for the preparation of SM-loaded liposomes containing a bile salt (SM-Lip-SEDS) was optimized using a central composite design of response surface methodology with the ratio of SM to phospholipids (w/w), flow rate of solution (mL/min), and pressure (MPa) as independent variables. Particle size, entrapment efficiency (EE), and drug loading (DL) were dependent variables for optimization of the process and formulation variables. The particle size, zeta potential, EE, and DL of the optimized SM-Lip-SEDS were 160.5 nm, −62.3 mV, 91.4%, and 4.73%, respectively. Two other methods to produce SM liposomes were compared to the SEDS method. The liposomes obtained by the SEDS method exhibited the highest EE and DL, smallest particle size, and best stability compared to liposomes produced by the thin-film dispersion and reversed-phase evaporation methods. Compared to the SM powder, SM-Lip-SEDS showed increased in vitro drug release. The in vivo AUC0−t of SM-Lip-SEDS was 4.8-fold higher than that of the SM powder. These results illustrate that liposomes containing a bile salt can be used to enhance the oral bioavailability of SM and that supercritical fluid technology is suitable for the preparation of liposomes. PMID:26543366

  14. Identification of the bile salt binding site on ipad from Shigella flexneri and the influence of ligand binding on IpaD structure

    SciTech Connect

    Barta, Michael L.; Guragain, Manita; Adam, Philip; Dickenson, Nicholas E.; Patil, Mrinalini; Geisbrecht, Brian V.; Picking, Wendy L.; Picking, William D.

    2012-10-25

    Type III secretion (TTS) is an essential virulence factor for Shigella flexneri, the causative agent of shigellosis. The Shigella TTS apparatus (TTSA) is an elegant nano-machine that is composed of a basal body, an external needle to deliver effectors into human cells, and a needle tip complex that controls secretion activation. IpaD is at the tip of the nascent TTSA needle where it controls the first step of TTS activation. The bile salt deoxycholate (DOC) binds to IpaD to induce recruitment of the translocator protein IpaB into the maturing tip complex. We recently used spectroscopic analyses to show that IpaD undergoes a structural rearrangement that accompanies binding to DOC. Here, we report a crystal structure of IpaD with DOC bound and test the importance of the residues that make up the DOC binding pocket on IpaD function. IpaD binds DOC at the interface between helices {alpha}3 and {alpha}7, with concomitant movement in the orientation of helix {alpha}7 relative to its position in unbound IpaD. When the IpaD residues involved in DOC binding are mutated, some are found to lead to altered invasion and secretion phenotypes. These findings suggest that adoption of a DOC-bound structural state for IpaD primes the Shigella TTSA for contact with host cells. The data presented here and in the studies leading up to this work provide the foundation for developing a model of the first step in Shigella TTS activation.

  15. Identification of the bile salt binding site on IpaD from Shigella flexneri and the influence of ligand binding on IpaD structure.

    PubMed

    Barta, Michael L; Guragain, Manita; Adam, Philip; Dickenson, Nicholas E; Patil, Mrinalini; Geisbrecht, Brian V; Picking, Wendy L; Picking, William D

    2012-03-01

    Type III secretion (TTS) is an essential virulence factor for Shigella flexneri, the causative agent of shigellosis. The Shigella TTS apparatus (TTSA) is an elegant nanomachine that is composed of a basal body, an external needle to deliver effectors into human cells, and a needle tip complex that controls secretion activation. IpaD is at the tip of the nascent TTSA needle where it controls the first step of TTS activation. The bile salt deoxycholate (DOC) binds to IpaD to induce recruitment of the translocator protein IpaB into the maturing tip complex. We recently used spectroscopic analyses to show that IpaD undergoes a structural rearrangement that accompanies binding to DOC. Here, we report a crystal structure of IpaD with DOC bound and test the importance of the residues that make up the DOC binding pocket on IpaD function. IpaD binds DOC at the interface between helices α3 and α7, with concomitant movement in the orientation of helix α7 relative to its position in unbound IpaD. When the IpaD residues involved in DOC binding are mutated, some are found to lead to altered invasion and secretion phenotypes. These findings suggest that adoption of a DOC bound structural state for IpaD primes the Shigella TTSA for contact with host cells. The data presented here and in the studies leading up to this work provide the foundation for developing a model of the first step in Shigella TTS activation.

  16. Identification of the bile salt binding site on IpaD from Shigella flexneri and the influence of ligand binding on IpaD structure

    PubMed Central

    Barta, Michael L.; Guragain, Manita; Adam, Philip; Dickenson, Nicholas E.; Patil, Mrinalini; Geisbrecht, Brian V.; Picking, Wendy L.; Picking, William D.

    2011-01-01

    Type III secretion (TTS) is an essential virulence factor for Shigella flexneri, the causative agent of shigellosis. The Shigella TTS apparatus (TTSA) is an elegant nano-machine that is composed of a basal body, an external needle to deliver effectors into human cells, and a needle tip complex that controls secretion activation. IpaD is at the tip of the nascent TTSA needle where it controls the first step of TTS activation. The bile salt deoxycholate (DOC) binds to IpaD to induce recruitment of the translocator protein IpaB into the maturing tip complex. We recently used spectroscopic analyses to show that IpaD undergoes a structural rearrangement that accompanies binding to DOC. Here we report a crystal structure of IpaD with DOC bound and test the importance of the residues that make up the DOC binding pocket on IpaD function. IpaD binds DOC at the interface between helices α3 and α7, with concomitant movement in the orientation of helix α7 relative to its position in unbound IpaD. When the IpaD residues involved in DOC binding are mutated, some are found to lead to altered invasion and secretion phenotypes. These findings suggest that adoption of a DOC-bound structural state for IpaD primes the Shigella TTSA for contact with host cells. The data presented here and in the studies leading up to this work provide the foundation for developing a model of the first step in Shigella TTS activation. PMID:22423359

  17. Self-assembly of aqueous bilirubin ditaurate, a natural conjugated bile pigment, to contraposing enantiomeric dimers and M(-) and P(+) tetramers and their selective hydrophilic disaggregation by monomers and micelles of bile salts.

    PubMed

    Neubrand, Michael W; Carey, Martin C; Laue, Thomas M

    2015-02-24

    The solution behavior of bilirubin ditaurate (BDT), the first naturally occurring conjugated bile pigment to be physically and chemically characterized, was assessed in aqueous solution and in monomeric and micellar solutions of common taurine-conjugated bile salts (BS). Analytical ultracentrifugation revealed that BDT self-associates in monomer-dimer equilibria between 1 and 500 μM, forming limiting tetramers at low millimolar concentrations. Self-association was enthalpically driven with ΔG values of ≈5 kcal/mol, suggesting strong hydrophobic interactions. Added NaCl and decreases in temperature shifted the oligomerization to lower BDT concentrations. On the basis of circular dichroism spectra and the limiting size of the self-aggregates, we infer that the tetramers are composed of 2P(+) and 2M(-) enantiomeric BDT pairs in "ridge-tile" conformations interacting in a "double-bookend" structure. With added monomeric BS, blue shifts in the UV-vis spectra and tight isosbestic points revealed that BDT/BS heterodimers form, followed by BDT "decorating" BS micelles mostly via hydrophilic interactions. Conformational enantiomerism, fluorescence intensities, and anisotropy, as well as resistance of the hybrid particles to disaggregation in 6 M urea, suggested that two or three hydrogen-bonding sites bound BDT monomers to the hydroxyl groups of BS, possibly via pyrrole-π-orbital-OH interactions. BDT stabilized these interactions by enveloping the BS in its "ridge-tile" pincers with variable strain that maximized van der Waals interactions. Possibly because the BDT molecule becomes highly strained with BS subtending a 7β-hydroxyl group, BDT became totally resistant to oxidation in air. This work predicts that, because of BS dissolution of the BDT self-aggregates, BS/bilirubin hybrid particles, which are stabilized hydrophilically, are likely to be the dominant mode of transport for all conjugated bilirubins in bile.

  18. Self-assembly of aqueous bilirubin ditaurate, a natural conjugated bile pigment, to contraposing enantiomeric dimers and M(-) and P(+) tetramers and their selective hydrophilic disaggregation by monomers and micelles of bile salts.

    PubMed

    Neubrand, Michael W; Carey, Martin C; Laue, Thomas M

    2015-02-24

    The solution behavior of bilirubin ditaurate (BDT), the first naturally occurring conjugated bile pigment to be physically and chemically characterized, was assessed in aqueous solution and in monomeric and micellar solutions of common taurine-conjugated bile salts (BS). Analytical ultracentrifugation revealed that BDT self-associates in monomer-dimer equilibria between 1 and 500 μM, forming limiting tetramers at low millimolar concentrations. Self-association was enthalpically driven with ΔG values of ≈5 kcal/mol, suggesting strong hydrophobic interactions. Added NaCl and decreases in temperature shifted the oligomerization to lower BDT concentrations. On the basis of circular dichroism spectra and the limiting size of the self-aggregates, we infer that the tetramers are composed of 2P(+) and 2M(-) enantiomeric BDT pairs in "ridge-tile" conformations interacting in a "double-bookend" structure. With added monomeric BS, blue shifts in the UV-vis spectra and tight isosbestic points revealed that BDT/BS heterodimers form, followed by BDT "decorating" BS micelles mostly via hydrophilic interactions. Conformational enantiomerism, fluorescence intensities, and anisotropy, as well as resistance of the hybrid particles to disaggregation in 6 M urea, suggested that two or three hydrogen-bonding sites bound BDT monomers to the hydroxyl groups of BS, possibly via pyrrole-π-orbital-OH interactions. BDT stabilized these interactions by enveloping the BS in its "ridge-tile" pincers with variable strain that maximized van der Waals interactions. Possibly because the BDT molecule becomes highly strained with BS subtending a 7β-hydroxyl group, BDT became totally resistant to oxidation in air. This work predicts that, because of BS dissolution of the BDT self-aggregates, BS/bilirubin hybrid particles, which are stabilized hydrophilically, are likely to be the dominant mode of transport for all conjugated bilirubins in bile. PMID:25671490

  19. Bile acid induced colonic irritation stimulates intracolonic nitric oxide release in humans.

    PubMed Central

    Casellas, F; Mourelle, M; Papo, M; Guarner, F; Antolin, M; Armengol, J R; Malagelada, J R

    1996-01-01

    AIM--To measure the intracolonic release of nitric oxide end products (nitrates plus nitrites) and eicosanoids in response to intraluminal irritation with deoxycholic acid (DCA). PATIENTS--Seven patients with irritable bowel syndrome. METHODS--The left colon was perfused with a solution with or without 3 mM deoxycholic acid. Aspirates were assayed for eicosanoids by specific radioimmuno-assay, and for nitrates plus nitrites by the Griess reaction. To confirm that stimulated colonic mucosa can produce nitric oxide (NO), ancillary studies were performed in vitro using samples of normal mucosa obtained from five surgically resected colons. Samples were incubated for 30 minutes in Kreb's solution, 3 mM DCA or DCA with 1 mM L-nitro-arginine-methyl-ester (L-NAME) to inhibit the NO synthase. Finally, NO synthase activity was measured in five samples of human colonic mucosa. RESULTS--Intracolonic release of nitrates plus nitrites was basally undetectable in six of seven patients. Bile acid considerably increased the release of prostaglandin E2 and nitrates plus nitrites (p < 0.01). By contrast, no increase in thromboxane and leukotriene was seen. In vitro mucosal incubation with DCA increased the production of NO synthase products, which was blocked by L-NAME. Activity of Ca+2 independent NO synthase was detectable in four of five samples of human colonic mucosa. CONCLUSION--The human colonic mucosa responds to bile acid induced irritation by a surge in NO generation via NO synthase. PMID:8707118

  20. Cholesterol-Lowering Potentials of Lactic Acid Bacteria Based on Bile-Salt Hydrolase Activity and Effect of Potent Strains on Cholesterol Metabolism In Vitro and In Vivo

    PubMed Central

    Lin, Pei-Pei; Hsieh, You-Miin; Zhang, Zi-yi; Wu, Hui-Ching; Huang, Chun-Chih

    2014-01-01

    This study collected different probiotic isolates from animal and plant sources to evaluate the bile-salt hydrolase activity of probiotics in vitro. The deconjugation potential of bile acid was determined using high-performance liquid chromatography. HepG2 cells were cultured with probiotic strains with high BSH activity. The triglyceride (TG) and apolipoprotein B (apo B) secretion by HepG2 cells were evaluated. Our results show that the BSH activity and bile-acid deconjugation abilities of Pediococcus acidilactici NBHK002, Bifidobacterium adolescentis NBHK006, Lactobacillus rhamnosus NBHK007, and Lactobacillus acidophilus NBHK008 were higher than those of the other probiotic strains. The cholesterol concentration in cholesterol micelles was reduced within 24 h. NBHK007 reduced the TG secretion by 100% after 48 h of incubation. NBHK002, NBHK006, and NBHK007 could reduce apo B secretion by 33%, 38%, and 39%, respectively, after 24 h of incubation. The product PROBIO S-23 produced a greater decrease in the total concentration of cholesterol, low-density lipoprotein, TG, and thiobarbituric acid reactive substance in the serum or livers of hamsters with hypercholesterolemia compared with that of hamsters fed with a high-fat and high-cholesterol diet. These results show that the three probiotic strains of lactic acid bacteria are better candidates for reducing the risk of cardiovascular disease. PMID:25538960

  1. Relationship between the effects of stress induced by human bile juice and acid treatment in Vibrio cholerae.

    PubMed

    Alvarez, Genoveva; Heredia, Norma; García, Santos

    2003-12-01

    The effects of low pH and human bile juice on Vibrio cholerae were investigated. A mild stress condition (exposure to acid shock at pH 5.5 or exposure to 3 mg of bile per ml for 20 min) slightly decreased (by < or = 1 log unit) V. cholerae cell viability. However, these treatments induced tolerance to subsequent exposures to more severe stress. In the O1 strain, four proteins were induced in response to acid shock (ca. 101, 94, 90, and 75 kDa), whereas only one protein (ca. 101 kDa) was induced in response to acid shock in the O139 strain. Eleven proteins were induced in response to bile shock in the O1 strain (ca. 106, 103, 101, 96, 88, 86, 84, 80, 66, 56, and 46 kDa), whereas only one protein was induced in response to bile shock in the O139 strain (ca. 88 kDa). V. cholerae O1 and O139 cells that had been preexposed to mild acid shock were twofold more resistant to pH 4.5 (with times required to inactivate 90% of the cell population [D-values] of 59 to 73 min) than were control cells (with D-values of 24 to 27 min). Likewise, cells that were preexposed to mild bile shock (3 mg/ml) were almost twofold more tolerant of severe bile shock (30 mg/ml; D-values, 68 to 87 min) than were control cells (with D-values of 37 to 43 min). These protective effects persisted for at least 1 h after the initial shock but were abolished when chloramphenicol was added to the culture during the shock. Cells preexposed to acid shock exhibited cross-protection against subsequent bile shock. However, cells preexposed to bile shock exhibited no changes in acid tolerance. Bile shock induced a modest reduction (0 to 20%) in enterotoxin production in V. cholerae, whereas acid shock had no effect on enterotoxin levels. Adaptation to acid and bile juice and protection against bile shock in response to preexposure to acid shock would be predicted to enhance the survival of V. cholerae in hosts and in foods. Thus, these adaptations may play an important role in the development of cholera

  2. Profiling serum bile acid glucuronides in humans: gender divergences, genetic determinants and response to fenofibrate

    PubMed Central

    Trottier, Jocelyn; Perreault, Martin; Rudkowska, Iwona; Levy, Cynthia; Dallaire-Theroux, Amélie; Verreault, Mélanie; Caron, Patrick; Staels, Bart; Vohl, Marie-Claude; Straka, Robert J.; Barbier, Olivier

    2014-01-01

    Glucuronidation, catalyzed by UDP-glucuronosyltransferase (UGT) enzymes detoxifies cholestatic bile acids (BAs). We aimed at i) characterizing the circulating BA-glucuronide (-G) pool composition in humans, ii) evaluating how sex and UGT polymorphisms influence this composition, and iii) analyzing the effects of lipid-lowering drug fenofibrate on the circulating BA-G profile in 300 volunteers and 5 cholestatic patients. Eleven BA-Gs were determined in pre- and post-fenofibrate samples. Men exhibited higher BA-G concentrations, and various genotype/BA-G associations were discovered in relevant UGT genes. The chenodeoxycholic acid-3G concentration was associated with the UGT2B7 802C>T polymorphism. Glucuronidation assays confirmed the predominant role of UGT2B7 and UGT1A4 in CDCA-3G formation. Fenofibrate exposure increased the serum levels of 5 BA-G species, including CDCA-3G, and up-regulated expression of UGT1A4, but not UGT2B7, in hepatic cells. This study demonstrates that fenofibrate stimulates BA glucuronidation in humans, and thus reduces bile acid toxicity in the liver. PMID:23756370

  3. Computational models for drug inhibition of the human apical sodium-dependent bile acid transporter.

    PubMed

    Zheng, Xiaowan; Ekins, Sean; Raufman, Jean-Pierre; Polli, James E

    2009-01-01

    The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid reabsorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, and a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested, and their K(i) values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or nonpotent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors. PMID:19673539

  4. Computational Models for Drug Inhibition of the Human Apical Sodium-dependent Bile Acid Transporter

    PubMed Central

    Zheng, Xiaowan; Ekins, Sean; Raufman, Jean-Pierre; Polli, James E.

    2009-01-01

    The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid re-absorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, as well as a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested and their Ki values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or non-potent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors. PMID:19673539

  5. Computational models for drug inhibition of the human apical sodium-dependent bile acid transporter.

    PubMed

    Zheng, Xiaowan; Ekins, Sean; Raufman, Jean-Pierre; Polli, James E

    2009-01-01

    The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid reabsorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, and a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested, and their K(i) values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or nonpotent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors.

  6. Effects of encapsulation on the viability of potential probiotic Lactobacillus plantarum exposed to high acidity condition and presence of bile salts.

    PubMed

    Tee, W F; Nazaruddin, R; Tan, Y N; Ayob, M K

    2014-09-01

    This study investigated the survival of encapsulated potential probiotic Lactobacillus plantarum which isolated from fermented cocoa beans. κ-Carrageenan was used to encapsulate the probiotic. Encapsulation techniques such as emulsification, freeze-drying or extrusion were adopted to encapsulate the probiotic. Freeze-drying and extrusion methods showed higher (p < 0.05) efficiency (89.48 ± 3.21 and 92.26 ± 1.45%, respectively) in encapsulating the probiotic compared to the emulsification method (82.19 ± 0.71% efficiency). Freeze-dried encapsulated probiotic L. plantarum was selected for further survival analysis as greater amount of beads were produced compared to the extrusion method. Freeze-dried probiotic was found to have significantly (p < 0.05) higher tolerance to acid at pH 2 with higher survival percentage compared to non-encapsulated probiotic. However, freeze-drying encapsulation was proven not to enhance the resistance of the probiotic to bile salt as evidenced by the one log colony reduction as for the non-encapsulated probiotic. Further modification of freeze-drying encapsulation technique is needed to enhance the survival of the encapsulated potential probiotic L. plantarum toward bile salt in the future.

  7. Microstructural evolution of lipid aggregates in nucleating model and human biles visualized by cryogenic transmission electron microscopy.

    PubMed

    Konikoff, F M; Danino, D; Weihs, D; Rubin, M; Talmon, Y

    2000-02-01

    Obtaining reliable information on the physical state and ultrastructure of bile is difficult because of its mixed aqueous-lipid composition and thermodynamic metastability. We have used time-lapse cryogenic transmission electron microscopy (cryo-TEM) combined with video-enhanced light microscopy (VELM) to study microstructural evolution in nucleating bile. A well-characterized model bile and gallbladder biles from cholesterol and pigment gallstone patients were studied sequentially during cholesterol nucleation and precipitation. In model bile, cholesterol crystallization was preceded by the appearance of the following distinct microstructures: spheroidal micelles (3-5 nm), discoidal membrane patches (50-150 nm) often in multiple layers (2-10), discs (50-100 nm), and unilamellar (50-200 nm) and larger multilamellar vesicles (MLVs). The membrane patches and discs appeared to be short-lived intermediates in a micelle-to-vesicle transition. Vesicular structures formed by growth and closure of patches as well as by budding off from vesicles with fewer bilayers. MLVs became more abundant, uniform, and concentric as a function of time. In native bile, all the above microstructures, except discoidal membrane patches, were observed. However, native MLVs were more uniform and concentric from the beginning. When cholesterol crystals appeared by light microscopy, MLVs were always detected by cryo-TEM. Edges of early cholesterol crystals were lined up with micelles and MLVs in a way suggesting an active role in feeding crystal growth from these microstructures. These findings, for the first time documented by cryo-TEM in human bile, provide a microstructural framework that can serve as a basis for investigation of specific factors that influence biliary cholesterol nucleation and crystal formation.

  8. Hydrophilic bile acids protect human blood-brain barrier endothelial cells from disruption by unconjugated bilirubin: an in vitro study

    PubMed Central

    Palmela, Inês; Correia, Leonor; Silva, Rui F. M.; Sasaki, Hiroyuki; Kim, Kwang S.; Brites, Dora; Brito, Maria A.

    2015-01-01

    Ursodeoxycholic acid and its main conjugate glycoursodeoxycholic acid are bile acids with neuroprotective properties. Our previous studies demonstrated their anti-apoptotic, anti-inflammatory, and antioxidant properties in neural cells exposed to elevated levels of unconjugated bilirubin (UCB) as in severe jaundice. In a simplified model of the blood-brain barrier, formed by confluent monolayers of a cell line of human brain microvascular endothelial cells, UCB has shown to induce caspase-3 activation and cell death, as well as interleukin-6 release and a loss of blood-brain barrier integrity. Here, we tested the preventive and restorative effects of these bile acids regarding the disruption of blood-brain barrier properties by UCB in in vitro conditions mimicking severe neonatal hyperbilirubinemia and using the same experimental blood-brain barrier model. Both bile acids reduced the apoptotic cell death induced by UCB, but only glycoursodeoxycholic acid significantly counteracted caspase-3 activation. Bile acids also prevented the upregulation of interleukin-6 mRNA, whereas only ursodeoxycholic acid abrogated cytokine release. Regarding barrier integrity, only ursodeoxycholic acid abrogated UCB-induced barrier permeability. Better protective effects were obtained by bile acid pre-treatment, but a strong efficacy was still observed by their addition after UCB treatment. Finally, both bile acids showed ability to cross confluent monolayers of human brain microvascular endothelial cells in a time-dependent manner. Collectively, data disclose a therapeutic time-window for preventive and restorative effects of ursodeoxycholic acid and glycoursodeoxycholic acid against UCB-induced blood-brain barrier disruption and damage to human brain microvascular endothelial cells. PMID:25821432

  9. Molecular cloning, chromosomal localization, and functional characterization of a human liver Na+/bile acid cotransporter.

    PubMed Central

    Hagenbuch, B; Meier, P J

    1994-01-01

    We have used a cDNA probe from a cloned rat liver Na+/taurocholate cotransporting polypeptide (Ntcp) to screen a human liver cDNA library. A 1,599-bp cDNA clone that encodes a human Na+/taurocholate cotransporting polypeptide (NTCP) was isolated. The human NTCP consists of 349 amino acids (calculated molecular mass of 38 kD) and exhibits 77% amino acid homology with the rat Ntcp. In vitro translation experiments indicate that the protein is glycosylated and has a molecular weight similar to the rat Ntcp. Injection of in vitro transcribed cRNA into Xenopus laevis oocytes resulted in the expression of Na(+)-dependent taurocholate uptake. Saturation kinetics indicated that the human NTCP has a higher affinity for taurocholate (apparent Km = 6 microM) than the previously cloned rat protein (apparent Km = 25 microM). NTCP-mediated taurocholate uptake into oocytes was inhibited by all major bile acid derivatives (100 microM), bumetanide (500 microM), and bromosulphophthalein (100 microM). Southern blot analysis of genomic DNA from a panel of human/hamster somatic cell hybrids mapped the human NTCP gene to chromosome 14. PMID:8132774

  10. The fate of the orally administered bile acid sequestrant, polidexide, in humans.

    PubMed

    Simons, L A

    1976-01-01

    1. The metabolic fate of the insoluble bile acid sequestrant polidexide, (poly-[2-(diethylamino)ethyl] polyglycerylenedextran hydrochloride), was studied in four adult humans following the oral administration of the 14C-labelled substance. 2. The mean cumulative recovery of 14C in faeces was 95-3% (s.e.m. = 1-1) of the administered dose, while mean cumulative recovery in urine was 0-37% (s.e.m. = 0-13) of the oral dose. 3. Only background levels of radioactivity were detectable in plasma samples taken 1-3 days after administration of tracer. 4. The findings suggested that polidexide was not absorbed from the gastrointestinal in man to any significant degree.

  11. Evidence for size and charge permselectivity of rat ascending colon. Effects of ricinoleate and bile salts on oxalic acid and neutral sugar transport.

    PubMed Central

    Kathpalia, S C; Favus, M J; Coe, F L

    1984-01-01

    We have measured unidirectional transmural fluxes of oxalate and neutral sugars across rat ascending colon in vitro, under short-circuit conditions, to characterize permeability barriers selective for size and charge. Ionic oxalate appears to be transported preferentially to sodium oxalate. Mucosal addition of taurocholate (1 mM), deoxycholate (1 mM), or ricinoleate (1 mM) increased bidirectional oxalate fluxes, and the ricinoleate effects were independent of medium calcium. Bidirectional fluxes of uncharged sugar molecules fell sharply at molecular weights above 76 (molecular radius above 3 A), and oxalate transport was retarded relative to that of uncharged molecules of similar size, suggesting that there is both size and charge permselectivity. Ricinoleate increased fluxes of all neutral molecules tested but changed neither the exclusion limits nor the cation selectivity of the epithelium. Bile salts and ricinoleate increase oxalate transport, probably by making more channels available, but do not alter size and charge selectivity. PMID:6432849

  12. The liver X-receptor alpha controls hepatic expression of the human bile acid-glucuronidating UGT1A3 enzyme in human cells and transgenic mice.

    PubMed

    Verreault, Mélanie; Senekeo-Effenberger, Kathy; Trottier, Jocelyn; Bonzo, Jessica A; Bélanger, Julie; Kaeding, Jenny; Staels, Bart; Caron, Patrick; Tukey, Robert H; Barbier, Olivier

    2006-08-01

    Glucuronidation, an important bile acid detoxification pathway, is catalyzed by enzymes belonging to the UDP-glucuronosyltransferase (UGT) family. Among UGT enzymes, UGT1A3 is considered the major human enzyme for the hepatic C24-glucuronidation of the primary chenodeoxycholic (CDCA) and secondary lithocholic (LCA) bile acids. We identify UGT1A3 as a positively regulated target gene of the oxysterol-activated nuclear receptor liver X-receptor alpha (LXRalpha). In human hepatic cells and human UGT1A transgenic mice, LXRalpha activators induce UGT1A3 mRNA levels and the formation of CDCA-24glucuronide (24G) and LCA-24G. Furthermore, a functional LXR response element (LXRE) was identified in the UGT1A3 promoter by site-directed mutagenesis, electrophoretic mobility shift assays and chromatin immunoprecipitation experiment. In addition, LXRalpha is found to interact with the SRC-1alpha and NCoR cofactors to regulate the UGT1A3 gene, but not with PGC-1beta. In conclusion, these observations establish LXRalpha as a crucial regulator of bile acid glucuronidation in humans and suggest that accumulation of oxysterols in hepatocytes during cholestasis favors bile acid detoxification as glucuronide conjugates. LXR agonists may be useful for stimulating both bile acid detoxification and cholesterol removal in cholestatic or hypercholesterolemic patients, respectively. PMID:16871576

  13. Biliary lipids, bile acids, and gallbladder function in the human female:effects of contraceptive steroids

    SciTech Connect

    Kern, F., Jr.; Everson, G.T.; DeMark, B.; McKinley, C.; Showalter, R.; Braverman, D.Z.; Szczepanik-Van Leeuwen, P.; Klein, P.D.

    1982-06-01

    Reported are biliary lipid composition and secretion, bile acid composition and kinetics, and gallbladder function in a group of healthy, nonobese women taking a contraceptive steroid preparation. A comparable group of healthy women served as controls. Biliary lipid secretion rate was measured by the marker perfusion technique. Bile acid distribution was determined by gas-lipid chromatography. The pool size, FTR, and synthesis rate of each bile acid were measured by using CA and CDCA labeled with the stable isotope of carbon, /sup 13/C. In some of the subjects gallbladder storage and emptying were measured during the kinetic study, by real-time ultrasonography. Contraceptive steroid use was associated with a significant increase in biliary cholesterol saturation and in the lithogenic index of bile. The rate of cholesterol secretion in the contraceptive steroid group was 50% greater than in the control (p << 0.001) and the rate of bile acid secretion was reduced (p < 0.02). The total bile acid pool size was significantly increased by contraceptive steroids. The major increase occurred in the CA pool (p < 0.04). The daily rate of enterohepatic cycles of the bile acid pool was decreased by contraceptive steroids from 6.6 to 4.3 (p < 0.01). The only effect of contraceptive steroids on gallbladder function was a slower emptying rate in response to intraduodenal amino acid infusion. No index of gallbladder function correlated significantly with any parameter of bile acid kinetics in this small group of subjects. The findings confirm the lithogenic effect of contraceptive steroids and indicate that its causes are an increase in cholesterol secretion and a decrease in bile acid secretion.

  14. Kinetics for the synthetic bile acid 75selenohomocholic acid-taurine in humans: comparison with [14C]taurocholate.

    PubMed

    Jazrawi, R P; Ferraris, R; Bridges, C; Northfield, T C

    1988-07-01

    The "apparent" fractional turnover rate of the gamma-labeled bile acid analogue 75selenohomocholic acid-taurine (75SeHCAT) was assessed from decline in radioactivity over the gallbladder area on 4 successive days using a gamma-camera, and was compared in the same subjects with the fractional turnover rate of the corresponding natural bile acid, cholic acid-taurine, labeled with 14C ([14C]CAT) using the classical Lindstedt technique. Very similar results were obtained in 5 healthy individuals (coefficient of variation 4.8%, medians 0.35 and 0.34, respectively). By contrast, the fractional deconjugation rate assessed from zonal scanning of glycine- and taurine-conjugated bile acids on thin-layer chromatography was much less for 75SeHCAT than for [14C]CAT (0.02 and 0.13, respectively; p less than 0.05). The fractional rate for deconjugation plus dehydroxylation was also determined by zonal scanning, and gave lower values for 75SeHCAT than for [14C]CAT (0.02 and 0.12, respectively; p less than 0.05). There was a striking similarity between the fractional rate for deconjugation alone and that for deconjugation plus dehydroxylation for both bile acids in individual samples (r = 0.999, p less than 0.001), suggesting that these two processes might occur simultaneously and probably involve the same bacteria. We conclude that our scintiscanning technique provides an accurate, noninvasive method of measuring fractional turnover rate of a bile acid in humans, and that the finding that 75SeHCAT remains conjugated with taurine during enterohepatic recycling means that absorption should be specific for the ileal active transport site, thus rendering it an ideal substance for assessing ileal function.

  15. Kinetics for the synthetic bile acid 75-selenohomocholic acid-taurine in humans: comparison with (/sup 14/C)taurocholate

    SciTech Connect

    Jazrawi, R.P.; Ferraris, R.; Bridges, C.; Northfield, T.C.

    1988-07-01

    The apparent fractional turnover rate of the gamma-labeled bile acid analogue 75-selenohomocholic acid-taurine (75-SeHCAT) was assessed from decline in radioactivity over the gallbladder area on 4 successive days using a gamma-camera, and was compared in the same subjects with the fractional turnover rate of the corresponding natural bile acid, cholic acid-taurine, labeled with 14C ((14C)CAT) using the classical Lindstedt technique. Very similar results were obtained in 5 healthy individuals (coefficient of variation 4.8%, medians 0.35 and 0.34, respectively). By contrast, the fractional deconjugation rate assessed from zonal scanning of glycine- and taurine-conjugated bile acids on thin-layer chromatography was much less for 75-SeHCAT than for (14C)CAT (0.02 and 0.13, respectively; p less than 0.05). The fractional rate for deconjugation plus dehydroxylation was also determined by zonal scanning, and gave lower values for 75-SeHCAT than for (14C)CAT (0.02 and 0.12, respectively; p less than 0.05). There was a striking similarity between the fractional rate for deconjugation alone and that for deconjugation plus dehydroxylation for both bile acids in individual samples (r = 0.999, p less than 0.001), suggesting that these two processes might occur simultaneously and probably involve the same bacteria. We conclude that our scintiscanning technique provides an accurate, noninvasive method of measuring fractional turnover rate of a bile acid in humans, and that the finding that 75SeHCAT remains conjugated with taurine during enterohepatic recycling means that absorption should be specific for the ileal active transport site, thus rendering it an ideal substance for assessing ileal function.

  16. Effects of bile duct ligation and captopril on salt appetite and renin-aldosterone axis in rats.

    PubMed

    Lane, J R; Starbuck, E M; Johnson, A K; Fitts, D A

    1999-05-01

    A ligation of the common bile duct (BDL) produces cholestasis and hypotension and increases the daily ingestion of sodium chloride solutions in rats. Low-dose captopril (CAP) treatment also modifies the ingestion of water and sodium in naive rats, and may do so in cholestatic rats. This study examined whether the elevated ingestion of saline by Long-Evans rats after BDL is associated with increased plasma renin activity (PRA), and whether treatment with a low dose of the angiotensin converting-enzyme inhibitor CAP further exacerbates fluid intake and PRA after BDL. In these experiments water and 0.3 M saline intake and PRA and plasma aldosterone (PA) were measured in naive and CAP-treated BDL and sham-ligated rats. We found that BDL elevated rats' daily saline intake 2 weeks after the ligation procedure but had no effect on PRA. CAP (0.1 mg/mL) placed in the drinking water of some BDL rats further increased saline intake. Both PA and hematocrits tended to be reduced in BDL rats, whereas PRA was elevated in both BDL and sham-ligated rats receiving CAP in the drinking water or by gavage (0.1 mg/mL in 10 mL/kg). The data suggest that the ingestion of saline by rats can be modified by BDL and CAP administration, but that exaggerated saline intake in BDL rats is not associated with excessive renin secretion. PMID:10357430

  17. Mitochondrial genome depletion in human liver cells abolishes bile acid-induced apoptosis: role of the Akt/mTOR survival pathway and Bcl-2 family proteins.

    PubMed

    Marin, Jose J G; Hernandez, Alicia; Revuelta, Isabel E; Gonzalez-Sanchez, Ester; Gonzalez-Buitrago, Jose M; Perez, Maria J

    2013-08-01

    Acute accumulation of bile acids in hepatocytes may cause cell death. However, during long-term exposure due to prolonged cholestasis, hepatocytes may develop a certain degree of chemoresistance to these compounds. Because mitochondrial adaptation to persistent oxidative stress may be involved in this process, here we have investigated the effects of complete mitochondrial genome depletion on the response to bile acid-induced hepatocellular injury. A subline (Rho) of human hepatoma SK-Hep-1 cells totally depleted of mitochondrial DNA (mtDNA) was obtained, and bile acid-induced concentration-dependent activation of apoptosis/necrosis and survival signaling pathways was studied. In the absence of changes in intracellular ATP content, Rho cells were highly resistant to bile acid-induced apoptosis and partially resistant to bile acid-induced necrosis. In Rho cells, both basal and bile acid-induced generation of reactive oxygen species (ROS), such as hydrogen peroxide and superoxide anion, was decreased. Bile acid-induced proapoptotic signals were also decreased, as evidenced by a reduction in the expression ratios Bax-α/Bcl-2, Bcl-xS/Bcl-2, and Bcl-xS/Bcl-xL. This was mainly due to a downregulation of Bax-α and Bcl-xS. Moreover, in these cells the Akt/mTOR pathway was constitutively activated in a ROS-independent manner and remained similarly activated in the presence of bile acid treatment. In contrast, ERK1/2 activation was constitutively reduced and was not activated by incubation with bile acids. In conclusion, these results suggest that impaired mitochondrial function associated with mtDNA alterations, which may occur in liver cells during prolonged cholestasis, may activate mechanisms of cell survival accounting for an enhanced resistance of hepatocytes to bile acid-induced apoptosis. PMID:23597504

  18. Consumer control of salt marshes driven by human disturbance.

    PubMed

    Bertness, Mark D; Silliman, Brian R

    2008-06-01

    Salt marsh ecosystems are widely considered to be controlled exclusively by bottom-up forces, but there is mounting evidence that human disturbances are triggering consumer control in western Atlantic salt marshes, often with catastrophic consequences. In other marine ecosystems, human disturbances routinely dampen (e.g., coral reefs, sea grass beds) and strengthen (e.g., kelps) consumer control, but current marsh theory predicts little potential interaction between humans and marsh consumers. Thus, human modification of top-down control in salt marshes was not anticipated and was even discounted in current marsh theory, despite loud warnings about the potential for cascading human impacts from work in other marine ecosystems. In spite of recent experiments that have challenged established marsh dogma and demonstrated consumer-driven die-off of salt marsh ecosystems, government agencies and nongovernmental organizations continue to manage marsh die-offs under the old theoretical framework and only consider bottom-up forces as causal agents. This intellectual dependency of many coastal ecologists and managers on system-specific theory (i.e., marsh bottom-up theory) has the potential to have grave repercussions for coastal ecosystem management and conservation in the face of increasing human threats. We stress that marine vascular plant communities (salt marshes, sea grass beds, mangroves) are likely more vulnerable to runaway grazing and consumer-driven collapse than is currently recognized by theory, particularly in low-diversity ecosystems like Atlantic salt marshes. PMID:18577090

  19. Consumer control of salt marshes driven by human disturbance.

    PubMed

    Bertness, Mark D; Silliman, Brian R

    2008-06-01

    Salt marsh ecosystems are widely considered to be controlled exclusively by bottom-up forces, but there is mounting evidence that human disturbances are triggering consumer control in western Atlantic salt marshes, often with catastrophic consequences. In other marine ecosystems, human disturbances routinely dampen (e.g., coral reefs, sea grass beds) and strengthen (e.g., kelps) consumer control, but current marsh theory predicts little potential interaction between humans and marsh consumers. Thus, human modification of top-down control in salt marshes was not anticipated and was even discounted in current marsh theory, despite loud warnings about the potential for cascading human impacts from work in other marine ecosystems. In spite of recent experiments that have challenged established marsh dogma and demonstrated consumer-driven die-off of salt marsh ecosystems, government agencies and nongovernmental organizations continue to manage marsh die-offs under the old theoretical framework and only consider bottom-up forces as causal agents. This intellectual dependency of many coastal ecologists and managers on system-specific theory (i.e., marsh bottom-up theory) has the potential to have grave repercussions for coastal ecosystem management and conservation in the face of increasing human threats. We stress that marine vascular plant communities (salt marshes, sea grass beds, mangroves) are likely more vulnerable to runaway grazing and consumer-driven collapse than is currently recognized by theory, particularly in low-diversity ecosystems like Atlantic salt marshes.

  20. Isolation and Profiling of MicroRNA-containing Exosomes from Human Bile.

    PubMed

    Li, Ling; Piontek, Klaus B; Kumbhari, Vivek; Ishida, Masaharu; Selaru, Florin M

    2016-01-01

    Exosome research in the last three years has greatly extended the scope towards identification and characterization of biomarkers and their therapeutic uses. Exosomes have recently been shown to contain microRNAs (miRs). MiRs themselves have arisen as valuable biomarkers for diagnostic purposes. As specimen collection in clinics and hospitals is quite variable, miRNA isolation from whole bile varies substantially. To achieve robust, accurate and reproducible miRNA profiles from collected bile samples in a simple manner required the development of a high-quality protocol to isolate and characterize exosomes from bile. The method requires several centrifugations and a filtration step with a final ultracentrifugation step to pellet the isolated exosomes. Electron microscopy, Western blots, flow cytometry and multi-parameter nanoparticle optical analysis, where available, are crucial characterization steps to validate the quality of the exosomes. For the isolation of miRNA from these exosomes, spiking the lysate with a non-specific, synthetic miRNA from a species like Caenorhabditis elegans, i.e., Cel-miR-39, is important for normalization of RNA extraction efficiency. The isolation of exosome from bile fluid following this method allows the successful miRNA profiling from bile samples stored for several years at -80 °C. PMID:27341293

  1. A possible role for bile acid in the control of methanogenesis and the accumulation of hydrogen gas in the human colon.

    PubMed

    Florin, T H; Jabbar, I A

    1994-01-01

    This study investigated a possible role for primary bile acid in the control of methanogenesis in the human colon. Production of hydrogen and methane was measured in anaerobic faecal cultures derived from faeces of six 'non-methanogenic' and three methanogenic healthy humans. Using a sensitive technique for gas measurement, methane was detected in all faecal cultures, including those from 'non-methanogenic' humans. Bile acid inhibited methanogenesis in a dose-response fashion in the in vitro 'non-methanogenic' and methanogenic faecal cultures. Inhibition was significant at bile acid concentrations > 0.05%. Methanogenesis correlated with methanogen (methanogenic bacteria) numbers. If this inhibition occurs in vivo, then it would explain much of the epidemiology of non-methanogenesis in humans. From an analysis of net hydrogen production by the faecal cultures, it is inferred that bile acid inhibits other hydrogen-consuming bacteria in addition to methanogens. These in vitro data suggest a major role for bile acid in the accumulation of hydrogen gas in the colon. Possible links between bile acid induced accumulation of gas and irritable bowel syndrome are discussed.

  2. Direct measurement of first-pass ileal clearance of a bile acid in humans

    SciTech Connect

    Galatola, G.; Jazrawi, R.P.; Bridges, C.; Joseph, A.E.; Northfield, T.C. )

    1991-04-01

    The purpose of this study was to develop and validate a method of directly measuring ileal bile acid absorption efficiency during a single enterohepatic cycle (first-pass ileal clearance). This has become feasible for the first time because of the availability of the synthetic gamma-labeled bile acid 75Selena-homocholic acid-taurine (75SeHCAT). Together with the corresponding natural bile acid cholic acid-taurine (labeled with 14C), SeHCAT was infused distal to an occluding balloon situated beyond the ampulla of Vater in six healthy subjects. Completion of a single enterohepatic cycle was assessed by obtaining a plateau for 75SeHCAT activity proximal to the occluding balloon, which prevented further cycles. Unabsorbed 75SeHCAT was collected after total gut washout, which was administered distal to the occluding balloon. 75SeHCAT activity in the rectal effluent measured by gamma counter was compared with that of absorbed 75SeHCAT level measured by gamma camera and was used to calculate first-pass ileal clearance. This was very efficient (mean value, 96%) and showed very little variation in the six subjects studied (range, 95%-97%). A parallel time-activity course in hepatic bile for 14C and 75Se during a single enterohepatic cycle, together with a ratio of unity for 14C/75Se in samples obtained at different time intervals, suggests that 75SeHCAT is handled by the ileum like the natural bile acid cholic acid-taurine. Extrapolation of 75SeHCAT first-pass ileal clearance to that of the natural bile acid therefore seems justifiable. In a subsidiary experiment, ileal absorption efficiency per day for 75SeHCAT was also measured by scanning the gallbladder area on 5 successive days after the measurement of first-pass ileal clearance. In contrast with absorption efficiency per cycle, absorption efficiency per day varied widely (49%-86%).

  3. Investigation of solubilising effects of bile salts on an active pharmaceutical ingredient with unusual pH dependent solubility by NMR spectroscopy.

    PubMed

    Vogtherr, M; Marx, A; Mieden, A-C; Saal, C

    2015-05-01

    The interaction between an ampholytic and amphiphilic Active Pharmaceutical Ingredient (API) showing unusual pH dependent solubility and Fasted State Simulated Intestinal Fluid (FaSSIF) was studied by NMR spectroscopy. Solubility in FaSSIF was drastically increased, about 30 fold, compared to simulated gastrointestinal fluid without bile salts. Our studies aimed at understanding the mechanisms that lead to this drastic enhancement. All species present in solution at various concentrations of API were characterised by Diffusion Ordered Spectroscopy (DOSY) NMR measurements. These indicated the presence of mixed taurocholate-lecithin and pure taurocholate micelles in pure FaSSIF, and formation of mixed taurocholate-API micelles after addition of API. The formation of taurocholate-API micelles was also supported by Nuclear Overhauser Effect/Enhancement (NOE) contacts between taurocholate and the API. Formation of mixed taurocholate-API micelles took place at the expense of pure taurocholate micelles, whereas mixed taurocholate-lecithin micelles remained uninfluenced by the presence of API. Our results showed that the increase in solubility was due to similar amphiphilic properties of the API and taurocholate which enabled formation of mixed taurocholate-API micelles. From results of determination of solubility as well as NMR experiments a phase diagram comprising several micellar species was derived. PMID:25720817

  4. Proliposomes containing a bile salt for oral delivery of Ginkgo biloba extract: Formulation optimization, characterization, oral bioavailability and tissue distribution in rats.

    PubMed

    Zheng, Bin; Teng, Lirong; Xing, Gaoyang; Bi, Ye; Yang, Shuang; Hao, Fei; Yan, Guodong; Wang, Xinmei; Lee, Robert J; Teng, Lesheng; Xie, Jing

    2015-09-18

    Proliposomes containing a bile salt were developed to improve the oral bioavailability of Ginkgo biloba extract (GbE). GbE loaded proliposomes (P-GbE) were successfully prepared by spray drying method. The formulation was optimized using the response surface methodology. FE-SEM, DSC, and FT-IR were used to study the surface morphology and molecular state of proliposomes, and demonstrated key interactions between the formulation ingredients. In vitro studies showed delayed release and enhanced dissolution of Ginkgo flavonoids and terpene lactones from GbE proliposomes. Proliposomes significantly enhanced GbE absorption in the gastrointestinal tract and decreased its elimination. The bioavailabilities of quercetin, kaempferol, isorhmnetin, ginkgolide A, ginkgolide B and ginkgolide C from proliposomes relative to the control were 245%, 211%, 264%, 203%, 333%, and 294%, respectively. Proliposomes were shown to selectively deliver GbE to critical target tissues. In conclusion, development of proliposomes formulation for GbE solved the problem of its poor oral bioavailability, prolonged its duration of action, and increased drug distribution in critical tissues, especially in the brain, therefore, warrant further investigation.

  5. Role of polymorphic bile salt export pump (BSEP, ABCB11) transporters in anti-tuberculosis drug-induced liver injury in a Chinese cohort

    PubMed Central

    Chen, Ru; Wang, Jing; Tang, Shaowen; Zhang, Yuan; Lv, Xiaozhen; Wu, Shanshan; Yang, Zhirong; Xia, Yinyin; Chen, Dafang; Zhan, Siyan

    2016-01-01

    Evidence indicates that the polymorphisms in bile salt export pump (BSEP, encoded by ABCB11) may play an important role in the development of anti-tuberculosis drug-induced liver injury (ATDILI) and we aim to investigate the association between genetic variants of ABCB11 and the risk of ATDILI in a Chinese cohort. A total of 89 tuberculosis patients with ATDILI and 356 matched ATDILI -free patients constituted cases and controls. Genetic polymorphisms of ABCB11 were determined by TaqMan single-nucleotide polymorphism (SNP) genotyping assay. Odds ratio (OR) with 95% confidence intervals (CIs) was estimated by conditional logistic regression model. There were no significant differences in genotype frequencies of ABCB11 between cases and controls. In the subgroup analysis, polymorphisms of rs2287616 were found to be associated with cholestatic/mixed pattern of liver injury under dominant and addictive model (OR = 3.84, 95% CI:1.16–12.75, P = 0.028 and OR = 2.51, 95% CI:1.12–5.62, P = 0.025, respectively), however the significance disappeared after Bonferroni correction. This study suggested that genetic variants of ABCB11 gene might contribute to anti-tuberculosis drug-induced cholestatic liver injury in Chinese patients. Studies in larger, varied populations are required to confirm these findings. PMID:27293027

  6. A novel vector for lactic acid bacteria that uses a bile salt hydrolase gene as a potential food-grade selection marker.

    PubMed

    Yin, Sheng; Zhai, Zhengyuan; Wang, Guohong; An, Haoran; Luo, Yunbo; Hao, Yanling

    2011-03-10

    A novel vector pM4aB for lactic acid bacterial was developed using a bile salt hydrolase gene from Lactobacillus plantarum as a potential food-grade selection marker. The 3.0-kb pM4aB consisted of the replicon of Lactobacillus plasmid pM4, a multiple cloning site and the bsh gene, which was constructed by elimination of a 5.5-kb non-food-grade DNA fragment from an 8.5-kb intermediate vector pBEmpM4aB. For electroporation into Lactobacillus paracasei X9, a high transformation efficiency of 4.0±1.0×10(4) CFU/μg plasmid DNA was yielded with 0.1% (wt/vol) glycodeoxycholic acid sodium selection. A high segregation stability of the vector was also observed as only 0.1% plasmid was lost after 50 generations of growth without selection pressure. The application potential of pM4aB was further confirmed by expression of a catalase gene from Lactobacillus sakei in L. paracasei. These results revealed that the novel vector pM4aB constructed in this study would be a useful tool for genetic modification of the industrially important LAB.

  7. Hypoglycemic activity and oral bioavailability of insulin-loaded liposomes containing bile salts in rats: the effect of cholate type, particle size and administered dose.

    PubMed

    Niu, Mengmeng; Lu, Yi; Hovgaard, Lars; Guan, Peipei; Tan, Yanan; Lian, Ruyue; Qi, Jianping; Wu, Wei

    2012-06-01

    Oral delivery of protein or polypeptide drugs remains a challenge due to gastric and enzymatic degradation as well as poor permeation across the intestinal epithelia. In this study, liposomes containing bile salts were developed as a new oral insulin delivery system. The primary goal was to investigate the effect of cholate type, particle size and dosage of the liposomes on the hypoglycemic activity and oral bioavailability. Liposomes containing sodium glycocholate (SGC), sodium taurocholate (STC) or sodium deoxycholate (SDC) were prepared by a reversed-phase evaporation method. After oral administration, all liposomes elicited a certain degree of hypoglycemic effect in parallel with an increase in blood insulin level. The highest oral bioavailability of approximately 8.5% and 11.0% could be observed with subcutaneous insulin as reference for SGC-liposomes in non-diabetic and diabetic rats, respectively. Insulin-loaded liposomes showed slower and sustained action over a period of over 20 h with peak time around 8-12h. SGC-liposomes showed higher oral bioavailability than liposomes containing STC or SDC and conventional liposomes. The hypoglycemic effect was size-dependent with the highest at 150 nm or 400 nm and was proportionally correlated to the administered dose. The results supported the hypothesis of insulin absorption as intact liposomes.

  8. Bile acid metabolism by fresh human colonic contents: a comparison of caecal versus faecal samples

    PubMed Central

    Thomas, L; Veysey, M; French, G; Hylemon, P; Murphy, G; Dowling, R

    2001-01-01

    BACKGROUND—Deoxycholic acid (DCA), implicated in the pathogenesis of gall stones and colorectal cancer, is mainly formed by bacterial deconjugation (cholylglycine hydrolase (CGH)) and 7α-dehydroxylation (7α-dehydroxylase (7α-DH)) of conjugated cholic acid (CA) in the caecum/proximal colon. Despite this, most previous studies of CGH and 7α-DH have been in faeces rather than in caecal contents. In bacteria, CA increases 7α-DH activity by substrate-enzyme induction but little is known about CA concentrations or CA/7α-DH induction in the human colon.
AIMS AND METHODS—Therefore, in fresh "faeces", and in caecal aspirates obtained during colonoscopy from 20 patients, we: (i) compared the activities of CGH and 7α-DH, (ii) measured 7α-DH in patients with "low" and "high" percentages of DCA in fasting serum (less than and greater than the median), (iii) studied CA concentrations in the right and left halves of the colon, and examined the relationships between (iv) 7α-DH activity and CA concentration in caecal samples (evidence of substrate-enzyme induction), and (v) 7α-DH and per cent DCA in serum.
RESULTS—Although mean CGH activity in the proximal colon (18.3 (SEM 4.40) ×10−2 U/mg protein) was comparable with that in "faeces" (16.0 (4.10) ×10− 2 U/mg protein) , mean 7α-DH in the caecum (8.54 (1.08) ×10-4 U/mg protein) was higher (p<0.05) than that in the left colon (5.72 (0.85) ×10-4 U/mg protein). At both sites, 7α-DH was significantly greater in the "high" than in the "low" serum DCA subgroups. CA concentrations in the right colon (0.94 (0.08) µmol/ml) were higher than those in the left (0.09 (0.03) µmol/ml; p<0.001) while in the caecum (but not in the faeces) there was a weak (r=0.58) but significant (p<0.005) linear relationship between 7α-DH and CA concentration. At both sites, 7α-DH was linearly related (p<0.005) to per cent DCA in serum.
INTERPRETATION/SUMMARY—These results: (i) confirm that there are marked regional

  9. Integrated Transcriptomic and Proteomic Analysis of the Bile Stress Response in a Centenarian-originated Probiotic Bifidobacterium longum BBMN68*

    PubMed Central

    An, Haoran; Douillard, François P.; Wang, Guohong; Zhai, Zhengyuan; Yang, Jin; Song, Shuhui; Cui, Jianyun; Ren, Fazheng; Luo, Yunbo; Zhang, Bing; Hao, Yanling

    2014-01-01

    Bifidobacteria are natural inhabitants of the human gastrointestinal tract and well known for their health-promoting effects. Tolerance to bile stress is crucial for bifidobacteria to survive in the colon and to exert their beneficial actions. In this work, RNA-Seq transcriptomic analysis complemented with proteomic analysis was used to investigate the cellular response to bile in Bifidobacterium longum BBMN68. The transcript levels of 236 genes were significantly changed (≥ threefold, p < 0.001) and 44 proteins were differentially abundant (≥1.6-fold, p < 0.01) in B. longum BBMN68 when exposed to 0.75 g l−1 ox-bile. The hemolysin-like protein and bile efflux systems were significantly over produced, which might prevent bile adsorption and exclude bile, respectively. The cell membrane composition was modified probably by an increase of cyclopropane fatty acid and a decrease of transmembrane proteins, resulting in a cell membrane more impermeable to bile salts. Our hypothesis was later confirmed by surface hydrophobicity assay. The transcription of genes related to xylose utilization and bifid shunt were up-regulated, which increased the production of ATP and reducing equivalents to cope with bile-induced damages in a xylan-rich colon environment. Bile salts signal the B. longum BBMN68 to gut entrance and enhance the expression of esterase and sortase associated with adhesion and colonization in intestinal tract, which was supported by a fivefold increased adhesion ability to HT-29 cells by BBMN68 upon bile exposure. Notably, bacterial one-hybrid and EMSA assay revealed that the two-component system senX3-regX3 controlled the expression of pstS in bifidobacteria and the role of this target gene in bile resistance was further verified by heterologous expression in Lactococcus lactis. Taken altogether, this study established a model for global response mechanisms in B. longum to bile. PMID:24965555

  10. Bile Acid Metabolism and Signaling

    PubMed Central

    Chiang, John Y. L.

    2015-01-01

    Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans. PMID:23897684

  11. Effect of calcium, magnesium and sodium ions on in vitro nucleation of human gall bladder bile.

    PubMed Central

    Neithercut, W D

    1989-01-01

    The effect of increasing the calcium, magnesium and sodium concentration in gall bladder bile samples from 21 patients with gall stones and nine controls on the in vitro rate of formation of cholesterol microcrystals and numbers of cholesterol microcrystals formed was examined. Addition of these cations to raise the mean maximum concentration of calcium ions to 19.8 mmol/l, of magnesium ions to 20 mmol/l and sodium ions to 998 mmol/l did not trigger nucleation in control bile samples or samples from patients with gall stones. Increasing the mean concentration of calcium ions to 8.6 mmol/l and of sodium to 320 mmol/l increased the numbers of cholesterol monohydrate crystals/0.1 mm3 counted by light polarisation phase contrast microscopy at the time of nucleation in samples from patients with gall stones from a median of 2 (range 1-10) in control portions to 18 (range 2-128) for calcium ions and 10 (range 2-141) for sodium ions (p less than 0.001). Calcium and magnesium ions were more effective than sodium ions, and calcium ions could increase crystal numbers at concentrations found in samples from patients with gall stones, median 4.6 mmol/l (range 2.7-16.9 mmol/l). The concentrations of calcium and magnesium present in bile may therefore influence the rate of development of gall stones. Images Fig. 1 PMID:2731760

  12. Conformational changes in IpaD from Shigella flexneri upon binding bile salts provide insight into the second step of type III secretion.

    PubMed

    Dickenson, Nicholas E; Zhang, Lingling; Epler, Chelsea R; Adam, Philip R; Picking, Wendy L; Picking, William D

    2011-01-18

    Shigella flexneri uses its type III secretion apparatus (TTSA) to inject host-altering proteins into targeted eukaryotic cells. The TTSA is composed of a basal body and an exposed needle with invasion plasmid antigen D (IpaD) forming a tip complex that controls secretion. The bile salt deoxycholate (DOC) stimulates recruitment of the translocator protein IpaB into the maturing TTSA needle tip complex. This process appears to be triggered by a direct interaction between DOC and IpaD. Fluorescence spectroscopy and NMR spectroscopy are used here to confirm the DOC-IpaD interaction and to reveal that IpaD conformational changes upon DOC binding trigger the appearance of IpaB at the needle tip. Förster resonance energy transfer between specific sites on IpaD was used here to identify changes in distances between IpaD domains as a result of DOC binding. To further explore the effects of DOC binding on IpaD structure, NMR chemical shift mapping was employed. The environments of residues within the proposed DOC binding site and additional residues within the "distal" globular domain were perturbed upon DOC binding, further indicating that conformational changes occur within IpaD upon DOC binding. These events are proposed to be responsible for the recruitment of IpaB at the TTSA needle tip. Mutation analyses combined with additional spectroscopic analyses confirm that conformational changes in IpaD induced by DOC binding contribute to the recruitment of IpaB to the S. flexneri TTSA needle tip. These findings lay the foundation for determining how environmental factors promote TTSA needle tip maturation prior to host cell contact.

  13. Toward Predicting Drug-Induced Liver Injury: Parallel Computational Approaches to Identify Multidrug Resistance Protein 4 and Bile Salt Export Pump Inhibitors

    PubMed Central

    Welch, Matthew A.; Köck, Kathleen; Urban, Thomas J.; Brouwer, Kim L. R.

    2015-01-01

    Drug-induced liver injury (DILI) is an important cause of drug toxicity. Inhibition of multidrug resistance protein 4 (MRP4), in addition to bile salt export pump (BSEP), might be a risk factor for the development of cholestatic DILI. Recently, we demonstrated that inhibition of MRP4, in addition to BSEP, may be a risk factor for the development of cholestatic DILI. Here, we aimed to develop computational models to delineate molecular features underlying MRP4 and BSEP inhibition. Models were developed using 257 BSEP and 86 MRP4 inhibitors and noninhibitors in the training set. Models were externally validated and used to predict the affinity of compounds toward BSEP and MRP4 in the DrugBank database. Compounds with a score above the median fingerprint threshold were considered to have significant inhibitory effects on MRP4 and BSEP. Common feature pharmacophore models were developed for MRP4 and BSEP with LigandScout software using a training set of nine well characterized MRP4 inhibitors and nine potent BSEP inhibitors. Bayesian models for BSEP and MRP4 inhibition/noninhibition were developed with cross-validated receiver operator curve values greater than 0.8 for the test sets, indicating robust models with acceptable false positive and false negative prediction rates. Both MRP4 and BSEP inhibitor pharmacophore models were characterized by hydrophobic and hydrogen-bond acceptor features, albeit in distinct spatial arrangements. Similar molecular features between MRP4 and BSEP inhibitors may partially explain why various drugs have affinity for both transporters. The Bayesian (BSEP, MRP4) and pharmacophore (MRP4, BSEP) models demonstrated significant classification accuracy and predictability. PMID:25735837

  14. Bile resistance mechanisms in Lactobacillus and Bifidobacterium

    PubMed Central

    Ruiz, Lorena; Margolles, Abelardo; Sánchez, Borja

    2013-01-01

    Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Most of the probiotic bacteria currently available in the market belong to the genera Lactobacillus and Bifidobacterium, and specific health-promoting activities, such as treatment of diarrhea or amelioration of gastrointestinal discomfort, have been attributed to them. In order to be able to survive the gastrointestinal transit and transiently colonize our gut, these bacteria must be able to counteract the deleterious action of bile salts, which are the main components of bile. Bile salts are detergent-like biological substances synthesized in the liver from cholesterol. Host enzymes conjugate the newly synthesized free bile acids in the liver with the amino acids glycine or taurine, generating conjugated bile salts. These compounds are stored in the gall bladder and they are released into the duodenum during digestion to perform their physiological function, which is the solubilization of fat coming from diet. These bile salts possess strong antimicrobial activity, since they are able to disorganize the structure of the cell membrane, as well as trigger DNA damage. This means that bacteria inhabiting our intestinal tract must have intrinsic resistance mechanisms to cope with bile salts. To do that, Lactobacillus and Bifidobacterium display a variety of proteins devoted to the efflux of bile salts or protons, to modify sugar metabolism or to prevent protein misfolding. In this manuscript, we review and discuss specific bile resistance mechanisms, as well as the processes responsible for the adaptation of bifidobacteria and lactobacilli to bile. PMID:24399996

  15. Conjugated and unconjugated bilirubins in bile of humans and rhesus monkeys. Structure of adult human and rhesus-monkey bilirubins compared with dog bilirubins.

    PubMed Central

    Blumenthal, S G; Taggart, D B; Ikeda, R; Ruebner, B; Bergstrom, D E

    1977-01-01

    1. Bilirubin-IXalpha, -IXalpha diglucuronide, -IXalpha monoglucuronide, -IXalpha monoglucoside -IXalpha monoxyloside, a bilirubin-IXalpha diconjugate containing glucose and another unknown compound, and bilirubin-IXbeta are present in gall-bladder bile of adult human, rhesus monkey and dog. Dog bile normally also contains other bilirubin-IXalpha diconjugates, i.e. compounds containing two conjugating sugars such as glucuronic acid and glucose, glucuronic acid and xylose and glucose xylose. 2. Azopigments alphaF, alphaO, alpha2, alpha3, betax and delta derived from human and rhesus-monkey bilirubins are identical in their chemical composition with those obtained from the dog. 3. Azopigments alphaF and betax found in diazotized biles of adult humans, rhesus monkeys and dogs are products of unconjugated bilirubin-IXbeta. 4. Technical modifications of previously published procedures [Heirwegh, Fevery, Michiels, Van Hees & Compernolle, (1975) Biochem. J. 145, 185-199] were introduced which make it possible to separate the bilirubins, diazotize the separated bilirubins, extract the azopigments and chromatograph them in one working day (6-8h). Images Fig. 1. Fig. 2. PMID:414741

  16. Structural elucidation of the hormonal inhibition mechanism of the bile acid cholate on human carbonic anhydrase II

    SciTech Connect

    Boone, Christopher D.; Tu, Chingkuang; McKenna, Robert

    2014-06-01

    The structure of human carbonic anhydrase II in complex with cholate has been determined to 1.54 Å resolution. Elucidation of the novel inhibition mechanism of cholate will aid in the development of a nonsulfur-containing, isoform-specific therapeutic agent. The carbonic anhydrases (CAs) are a family of mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO{sub 2} into bicarbonate and a proton. Human isoform CA II (HCA II) is abundant in the surface epithelial cells of the gastric mucosa, where it serves an important role in cytoprotection through bicarbonate secretion. Physiological inhibition of HCA II via the bile acids contributes to mucosal injury in ulcerogenic conditions. This study details the weak biophysical interactions associated with the binding of a primary bile acid, cholate, to HCA II. The X-ray crystallographic structure determined to 1.54 Å resolution revealed that cholate does not make any direct hydrogen-bond interactions with HCA II, but instead reconfigures the well ordered water network within the active site to promote indirect binding to the enzyme. Structural knowledge of the binding interactions of this nonsulfur-containing inhibitor with HCA II could provide the template design for high-affinity, isoform-specific therapeutic agents for a variety of diseases/pathological states, including cancer, glaucoma, epilepsy and osteoporosis.

  17. Differential activation of the human farnesoid X receptor depends on the pattern of expressed isoforms and the bile acid pool composition.

    PubMed

    Vaquero, Javier; Monte, Maria J; Dominguez, Mercedes; Muntané, Jordi; Marin, Jose J G

    2013-10-01

    The farnesoid X receptor (FXR) is a key sensor in bile acid homeostasis. Although four human FXR isoforms have been identified, the physiological role of this diversity is poorly understood. Here we investigated their subcellular localization, agonist sensitivity and response of target genes. Measurement of mRNA revealed that liver predominantly expressed FXRα1(+/-), whereas FXRα2(+/-) were the most abundant isoforms in kidney and intestine. In all cases, the proportion of FXRα(1/2)(+) and FXRα(1/2)(-) isoforms, i.e., with and without a 12bp insert, respectively, was approximately 50%. When FXR was expressed in liver and intestinal cells the magnitude of the response to GW4064 and bile acids differs among FXR isoforms. In both cell types the strongest response was that of FXRα1(-). Different efficacy of bile acids species to activate FXR was found. The four FXR isoforms shared the order of sensitivity to bile acids species. When in FXR-deficient cells FXR was transfected, unconjugated, but not taurine- and glycine-amidated bile acids, were able to activate FXR. In contrast, human hepatocytes and cell lines showing an endogenous expression of FXR were sensitive to both unconjugated and conjugated bile acids. This suggests that to activate FXR conjugated, but not unconjugated, bile acids require additional component(s) of the intracellular machinery not related with uptake processes, which are missing in some tumor cells. In conclusion, cell-specific pattern of FXR isoforms determine the overall tissue sensitivity to FXR agonists and may be involved in the differential response of FXR target genes to FXR activation.

  18. The mediators of bile action on the exocrine pancreas.

    PubMed

    Riepl, R L; Lehnert, P

    1993-05-01

    Under basal conditions, bile and bile salts applied intraduodenally influence plasma levels of several gastroenteropancreatic peptides. Besides those with stimulatory effects on exocrine pancreatic secretion, others with inhibitory or no effects are released as well. Furthermore, cholinergic and peptidergic neural mechanisms may also be activated. Secretin seems to be the most important mediator of bile- or bile salt-induced water and bicarbonate secretion. In addition, VIP released from peptidergic nerve endings in the pancreas may also be involved in the mediation of the hydrokinetic effect. With regard to water and bicarbonate secretion, cholinergic mechanisms probably are of minor importance. Cholinergic mechanisms, however, seem to be the most important mediator of bile- or bile salt-induced pancreatic enzyme secretion. CCK may act as an additional mediator of the ecbolic effect. This statement, however, is based on few results only and has to be confirmed by further studies. Gastroenteropancreatic peptides with an inhibitory action on the exocrine pancreas were also released by intraduodenal bile or bile salts. Somatostatin is released in physiologically relevant amounts to bring about a counter-regulation. Plasma PP levels are also enhanced by bile and bile salts. The amounts of PP released, however, are below those observed postprandially. In contrast to their stimulatory action on basal pancreatic secretion, bile and bile salts have no or even an inhibitory effect on pancreatic secretion stimulated by intraluminal nutrients. Accordingly, the release of gastroenteropancreatic peptides is not influenced (for example, secretin) or even reduced (for example, CCK) when bile or bile salts are added to intraluminal nutrients.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. The mediators of bile action on the exocrine pancreas.

    PubMed

    Riepl, R L; Lehnert, P

    1993-05-01

    Under basal conditions, bile and bile salts applied intraduodenally influence plasma levels of several gastroenteropancreatic peptides. Besides those with stimulatory effects on exocrine pancreatic secretion, others with inhibitory or no effects are released as well. Furthermore, cholinergic and peptidergic neural mechanisms may also be activated. Secretin seems to be the most important mediator of bile- or bile salt-induced water and bicarbonate secretion. In addition, VIP released from peptidergic nerve endings in the pancreas may also be involved in the mediation of the hydrokinetic effect. With regard to water and bicarbonate secretion, cholinergic mechanisms probably are of minor importance. Cholinergic mechanisms, however, seem to be the most important mediator of bile- or bile salt-induced pancreatic enzyme secretion. CCK may act as an additional mediator of the ecbolic effect. This statement, however, is based on few results only and has to be confirmed by further studies. Gastroenteropancreatic peptides with an inhibitory action on the exocrine pancreas were also released by intraduodenal bile or bile salts. Somatostatin is released in physiologically relevant amounts to bring about a counter-regulation. Plasma PP levels are also enhanced by bile and bile salts. The amounts of PP released, however, are below those observed postprandially. In contrast to their stimulatory action on basal pancreatic secretion, bile and bile salts have no or even an inhibitory effect on pancreatic secretion stimulated by intraluminal nutrients. Accordingly, the release of gastroenteropancreatic peptides is not influenced (for example, secretin) or even reduced (for example, CCK) when bile or bile salts are added to intraluminal nutrients.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8099758

  20. Therapeutic uses of animal biles in traditional Chinese medicine: An ethnopharmacological, biophysical chemical and medicinal review

    PubMed Central

    Wang, David Q-H; Carey, Martin C

    2014-01-01

    Forty-four different animal biles obtained from both invertebrates and vertebrates (including human bile) have been used for centuries for a host of maladies in traditional Chinese medicine (TCM) beginning with dog, ox and common carp biles approximately in the Zhou dynasty (c. 1046-256 BCE). Overall, different animal biles were prescribed principally for the treatment of liver, biliary, skin (including burns), gynecological and heart diseases, as well as diseases of the eyes, ears, nose, mouth and throat. We present an informed opinion of the clinical efficacy of the medicinal uses of the different animal biles based on their presently known principal chemical components which are mostly steroidal detergent-like molecules and the membrane lipids such as unesterified cholesterol and mixed phosphatidylcholines and sometimes sphingomyelin, as well as containing lipopigments derived from heme principally bilirubin glucuronides. All of the available information on the ethnopharmacological uses of biles in TCM were collated from the rich collection of ancient Chinese books on materia medica held in libraries in China and United States and the composition of various animal biles was based on rigorous separatory and advanced chemical identification techniques published since the mid-20th century collected via library (Harvard’s Countway Library) and electronic searches (PubMed and Google Scholar). Our analysis of ethnomedical data and information on biliary chemistry shows that specific bile salts, as well as the common bile pigment bilirubin and its glucuronides plus the minor components of bile such as vitamins A, D, E, K, as well as melatonin (N-acetyl-5-methoxytryptamine) are salutary in improving liver function, dissolving gallstones, inhibiting bacterial and viral multiplication, promoting cardiac chronotropsim, as well as exhibiting anti-inflammatory, anti-pyretic, anti-oxidant, sedative, anti-convulsive, anti-allergic, anti-congestive, anti-diabetic and anti

  1. Therapeutic uses of animal biles in traditional Chinese medicine: an ethnopharmacological, biophysical chemical and medicinal review.

    PubMed

    Wang, David Q-H; Carey, Martin C

    2014-08-01

    Forty-four different animal biles obtained from both invertebrates and vertebrates (including human bile) have been used for centuries for a host of maladies in traditional Chinese medicine (TCM) beginning with dog, ox and common carp biles approximately in the Zhou dynasty (c. 1046-256 BCE). Overall, different animal biles were prescribed principally for the treatment of liver, biliary, skin (including burns), gynecological and heart diseases, as well as diseases of the eyes, ears, nose, mouth and throat. We present an informed opinion of the clinical efficacy of the medicinal uses of the different animal biles based on their presently known principal chemical components which are mostly steroidal detergent-like molecules and the membrane lipids such as unesterified cholesterol and mixed phosphatidylcholines and sometimes sphingomyelin, as well as containing lipopigments derived from heme principally bilirubin glucuronides. All of the available information on the ethnopharmacological uses of biles in TCM were collated from the rich collection of ancient Chinese books on materia medica held in libraries in China and United States and the composition of various animal biles was based on rigorous separatory and advanced chemical identification techniques published since the mid-20(th) century collected via library (Harvard's Countway Library) and electronic searches (PubMed and Google Scholar). Our analysis of ethnomedical data and information on biliary chemistry shows that specific bile salts, as well as the common bile pigment bilirubin and its glucuronides plus the minor components of bile such as vitamins A, D, E, K, as well as melatonin (N-acetyl-5-methoxytryptamine) are salutary in improving liver function, dissolving gallstones, inhibiting bacterial and viral multiplication, promoting cardiac chronotropsim, as well as exhibiting anti-inflammatory, anti-pyretic, anti-oxidant, sedative, anti-convulsive, anti-allergic, anti-congestive, anti-diabetic and anti

  2. The ulcerogenic effect of bile and bile acid in rats during immobilization stress

    NASA Technical Reports Server (NTRS)

    Weisener, J.

    1980-01-01

    The effect of different concentrations of oxen bile and individual bile acids or their sodium salts on the gastric mucosa of rats was investigated in combination with immobilization stress. A statistically significant higher frequency of ulcers was only determined in the application of 10% oxen bile. Dosages on 10% sodium glycocholic acid demonstrated strong toxic damage with atonic dilation of the stomach and extensive mucosal bleeding.

  3. Gender, but not CYP7A1 or SLCO1B1 polymorphism, affects the fasting plasma concentrations of bile acids in human beings.

    PubMed

    Xiang, Xiaoqiang; Backman, Janne T; Neuvonen, Pertti J; Niemi, Mikko

    2012-03-01

    Cholesterol 7α-hydroxylase (CYP7A1) is the rate-limiting enzyme of bile acid production in human beings, and organic anion-transporting polypeptide 1B1 (OATP1B1) may influence bile acid hepatic uptake and cholesterol and bile acid synthesis rate. Our purpose was to investigate the effects of gender and CYP7A1 and SLCO1B1 polymorphisms on the fasting plasma concentrations of bile acids, bile acid synthesis marker and total cholesterol in a Finnish population. Fasting plasma concentrations of 16 endogenous bile acids, their synthesis marker (7α-hydroxy-4-cholesten-3-one) and total cholesterol were measured in 243 samples from 143 healthy volunteers. The volunteers were genotyped for 6 haplotype-tagging single-nucleotide polymorphisms (SNPs) of CYP7A1 and two functionally relevant SNPs in SLCO1B1. The mean plasma concentrations of chenodeoxycholic acid, glycochenodeoxycholic acid, ursodeoxycholic acid and glycoursodeoxycholic acid were 61-111% higher in men than in women (P ≤ 0.001). Accordingly, the mean concentration of total bile acids was 51% higher in men than in women (P = 0.001). The CYP7A1 rs8192879 and rs1023652 SNPs were associated with deoxycholic acid and hyodeoxycholic acid concentrations, respectively, but the associations were not significant after correction for multiple testing. None of the six CYP7A1 SNPs was associated with the plasma concentrations of cholesterol or 7α-hydroxy-4-cholesten-3-one. SLCO1B1 genotype was associated with total plasma cholesterol concentration only, but the association was not significant after correction for multiple testing. In general, the gender contributes substantially more to variation in fasting plasma bile acid concentrations than CYP7A1 or SLCO1B1 polymorphism do. Common genetic variability in CYP7A1 is unlikely to play a significant role in cholesterol metabolism and bile acid homeostasis under normal physiological conditions.

  4. Transmembrane domain V plays a stabilizing role in the function of human bile acid transporter SLC10A2.

    PubMed

    Moore, Robyn H; Chothe, Paresh; Swaan, Peter W

    2013-07-30

    The human apical sodium-dependent bile acid transporter (hASBT, SLC10A2), primarily expressed in the ileum, is involved in both the recycling of bile acids and cholesterol homeostasis. In this study, the structure-function relationship of transmembrane domain 5 (TM5) residues involved in transport is elucidated. Cysteine scanning mutagenesis of each consecutive residue on TM5 resulted in 96% of mutants having a significantly decreased transport activity, although each was expressed at the cell surface. Specifically, G197 and I208 were no longer functional, and G201 and G212 functioned at a level of <10% upon cysteine mutation. Interestingly, each of these exists along one face of the helix. Studies suggest that neither G201 nor G212 is on the substrate pathway. Conservative alanine mutations of the four residues displayed a higher activity in all but G197A, indicating its functional importance. G197 and G201 form a GxxxG motif, which has been found to be important in helix-helix interactions. According to our model, G197 and G201 face transmembrane domain 4 (TM4) residues G179 and P175, respectively. Similarly, G212 faces G237, which forms part of a GxxxG domain in transmembrane domain 6 (TM6). It is possible that these GxxxG domains and their interacting partners are responsible for maintaining the structure of the helices and their interactions with one another. I205 and I208 are both in positions to anchor the GxxxG domains and direct the change in interaction of TM5 from TM4 to TM6. Combined, the results suggest that residues along TM5 are critical for ASBT function but are not directly involved in substrate translocation.

  5. Tissue-specific bioaccumulation of human and veterinary antibiotics in bile, plasma, liver and muscle tissues of wild fish from a highly urbanized region.

    PubMed

    Zhao, Jian-Liang; Liu, You-Sheng; Liu, Wang-Rong; Jiang, Yu-Xia; Su, Hao-Chang; Zhang, Qian-Qian; Chen, Xiao-Wen; Yang, Yuan-Yuan; Chen, Jun; Liu, Shuang-Shuang; Pan, Chang-Gui; Huang, Guo-Yong; Ying, Guang-Guo

    2015-03-01

    We investigated the bioaccumulation of antibiotics in bile, plasma, liver and muscle tissues of wild fish from four rivers in the Pearl River Delta region. In total, 12 antibiotics were present in at least one type of fish tissues from nine wild fish species in the four rivers. The mean values of log bioaccumulation factors (log BAFs) for the detected antibiotics in fish bile, plasma, liver, and muscle tissues were at the range of 2.06-4.08, 1.85-3.47, 1.41-3.51, and 0.48-2.70, respectively. As the digestion tissues, fish bile, plasma, and liver showed strong bioaccumulation ability for some antibiotics, indicating a different bioaccumulation pattern from hydrophobic organic contaminants. Human health risk assessment based on potential fish consumption indicates that these antibiotics do not appear to pose an appreciable risk to human health. To the best of our knowledge, this is first report of bioaccumulation patterns of antibiotics in wild fish bile and plasma.

  6. Bile acids as metabolic regulators

    PubMed Central

    Li, Tiangang; Chiang, John Y. L.

    2015-01-01

    Summary Small molecule ligands that target to TGR5 and FXR have shown promise in treating various metabolic and inflammation-related human diseases. New insights into the mechanisms underlying the bariatric surgery and bile acid sequestrant treatment suggest that targeting the enterohepatic circulation to modulate gut-liver bile acid signaling, incretin production and microbiota represents a new strategy to treat obesity and type-2 diabetes. PMID:25584736

  7. Differential effect of troglitazone on the human bile acid transporters, MRP2 and BSEP, in the PXB hepatic chimeric mouse.

    PubMed

    Foster, John R; Jacobsen, Matt; Kenna, Gerry; Schulz-Utermoehl, Timothy; Morikawa, Yoshio; Salmu, Juuso; Wilson, Ian D

    2012-12-01

    The aims of this study were to assess the utility of the PXB mouse model of a chimeric human/mouse liver in studying human-specific effects of an important human hepatotoxic drug, the PPARγ agonist, troglitazone. When given orally by gavage for 7 days, at dose levels of 300 and 600 ppm, troglitazone induced specific changes in the human hepatocytes of the chimeric liver without an effect on the murine hepatic portions. The human hepatocytes, in the vehicle-treated PXB mouse, showed an accumulation of electron-dense lipid droplets that appeared as clear vacuoles under the light microscope in H&E-stained sections. Following dosing with troglitazone, there was a loss of the large lipid droplets in the human hepatocytes, a decrease in the amount of lipid as observed in frozen sections of liver stained by Oil-red-O, and a decrease in the expression of two bile acid transporters, BSEP and MRP2. None of these changes were observed in the murine remnants of the chimeric liver. No changes were observed in the expression of three CYPs, CYP 3A2, CYP 1A1, and CYP 2B1, in either the human or murine hepatocytes, even though the baseline expression of the enzymes differed significantly between the two hepatocyte species with the mouse hepatocytes consistently showing increased expression of the protein of all three enzymes. This study has shown that the human hepatocytes, in the PXB chimeric mouse liver, retain an essentially normal phenotype in the mouse liver and, the albeit limited CYP enzymes studied show a more human, rather than a murine, expression pattern. In line with this conclusion, the study has shown a differential response of the human versus the mouse hepatocytes, and the effects observed are highly suggestive of a differential handling of the compound by the two hepatocyte species although the exact reasons are not as yet clear. The PXB chimeric mouse system therefore holds the clear potential to explore human hepatic-specific features, such as metabolism, prior

  8. Serum Bile Acids Are Higher in Humans With Prior Gastric Bypass: Potential Contribution to Improved Glucose and Lipid Metabolism

    PubMed Central

    Patti, Mary-Elizabeth; Houten, Sander M.; Bianco, Antonio C.; Bernier, Raquel; Larsen, P. Reed; Holst, Jens J.; Badman, Michael K.; Maratos-Flier, Eleftheria; Mun, Edward C.; Pihlajamaki, Jussi; Auwerx, Johan; Goldfine, Allison B.

    2015-01-01

    The multifactorial mechanisms promoting weight loss and improved metabolism following Roux-en-Y gastric bypass (GB) surgery remain incompletely understood. Recent rodent studies suggest that bile acids can mediate energy homeostasis by activating the G-protein coupled receptor TGR5 and the type 2 thyroid hormone deiodinase. Altered gastrointestinal anatomy following GB could affect enterohepatic recirculation of bile acids. We assessed whether circulating bile acid concentrations differ in patients who previously underwent GB, which might then contribute to improved metabolic homeostasis. We performed cross-sectional analysis of fasting serum bile acid composition and both fasting and post-meal metabolic variables, in three subject groups: (i) post-GB surgery (n = 9), (ii) without GB matched to preoperative BMI of the index cohort (n = 5), and (iii) without GB matched to current BMI of the index cohort (n = 10). Total serum bile acid concentrations were higher in GB (8.90 ± 4.84 µmol/l) than in both overweight (3.59 ± 1.95, P = 0.005, Ov) and severely obese (3.86 ± 1.51, P = 0.045, MOb). Bile acid subfractions taurochenodeoxycholic, taurodeoxycholic, glycocholic, glycochenodeoxycholic, and glycodeoxycholic acids were all significantly higher in GB compared to Ov (P < 0.05). Total bile acids were inversely correlated with 2-h post-meal glucose (r = −0.59, P < 0.003) and fasting triglycerides (r = −0.40, P = 0.05), and positively correlated with adiponectin (r = −0.48, P < 0.02) and peak glucagon-like peptide-1 (GLP-1) (r = 0.58, P < 0.003). Total bile acids strongly correlated inversely with thyrotropic hormone (TSH) (r = −0.57, P = 0.004). Together, our data suggest that altered bile acid levels and composition may contribute to improved glucose and lipid metabolism in patients who have had GB. PMID:19360006

  9. Resistance to butyrate impairs bile acid-induced apoptosis in human colon adenocarcinoma cells via up-regulation of Bcl-2 and inactivation of Bax.

    PubMed

    Barrasa, Juan I; Santiago-Gómez, Angélica; Olmo, Nieves; Lizarbe, María Antonia; Turnay, Javier

    2012-12-01

    A critical risk factor in colorectal carcinogenesis and tumor therapy is the resistance to the apoptotic effects of different compounds from the intestinal lumen, among them butyrate (main regulator of colonic epithelium homeostasis). Insensitivity to butyrate-induced apoptosis yields resistance to other agents, as bile acids or chemotherapy drugs, allowing the selective growth of malignant cell subpopulations. Here we analyze bile acid-induced apoptosis in a butyrate-resistant human colon adenocarcinoma cell line (BCS-TC2.BR2) to determine the mechanisms that underlay the resistance to these agents in comparison with their parental butyrate-sensitive BCS-TC2 cells. This study demonstrates that DCA and CDCA still induce apoptosis in butyrate-resistant cells through increased ROS production by activation of membrane-associated enzymes and subsequent triggering of the intrinsic mitochondrial apoptotic pathway. Although this mechanism is similar to that described in butyrate-sensitive cells, cell viability is significantly higher in resistant cells. Moreover, butyrate-resistant cells show higher Bcl-2 levels that confer resistance to bile acid-induced apoptosis sequestering Bax and avoiding Bax-dependent pore formation in the mitochondria. We have confirmed that this resistance is reverted using the Bcl-2 inhibitor ABT-263, thus demonstrating that the lower sensitivity of butyrate-resistant cells to the apoptotic effects of bile acids is mainly due to increased Bcl-2 levels.

  10. Quasielastic light scattering studies of aqueous biliary lipid systems and native bile.

    PubMed

    Mazer, N A

    1990-09-01

    During the past 15 yr, the technique of quasielastic light scattering has been used by a number of laboratories to systematically investigate the aggregative behavior of model bile systems and more recently to characterize particles present in native bile. Quasielastic light scattering investigations of aqueous bile salt solutions have indicated important similarities and differences between the various bile salt species and have led to a quantitative model for the formation of globular and rodlike micelles, based on Small and Ekwall's primary-secondary micelle hypothesis. Studies of aqueous bile salt-lecithin systems have indicated three important aggregation regimens dependent on the lecithin/bile salt molar ratio and total solute concentration. Region I of the phase diagram, which includes the lecithin/bile salt and total solute concentration values found in most mammalian biles, corresponds to a population of "simple" bile salt micelles coexisting in equilibrium with a population of mixed bile salt-lecithin micelles. Region II contains only mixed micelles, whose apparent size and shape vary with lecithin/bile salt and total solute concentration in a manner consistent with a "mixed disc" model. In this model, bile salts not only coat the perimeter of the disc (as proposed in Small's original model) but are also incorporated within the lecithin bilayer, possibly as hydrogen-bonded dimers. Finally, in region III, where total solute concentration values are typically less than the critical micelle concentration of the pure bile salt, the systems contain mixed vesicles (spherical bilayer shells) whose size (approximately 130 to 500A) depends on lecithin/bile salt and total solute concentration in accordance with a simple partition equilibrium that determines the composition of the mixed vesicle bilayer.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Physical chemistry of biliary lipids during bile formation.

    PubMed

    Cohen, D E; Carey, M C

    1990-09-01

    Present concepts suggest that the canalicular secretion of bile salts is monomeric, which in turn drives the hepatic secretion of lecithin and cholesterol presumably as unilamellar vesicles into bile. As biliary lipids are concentrated within the biliary tree and gallbladder, bile salts structurally alter lecithin-cholesterol vesicles to form a variety of metastable aggregates whose structures and phase transformations are predicted by phase equilibria considerations. These structural transformations ultimately result in the dispersion of biliary lipids as thermodynamically stable micelles or micelles plus thermodynamically unstable vesicles in common duct and gallbladder biles. The experiments reviewed herein represent experimental simulations of these processes. We used pure aqueous lipid systems to model the putative stages of biliary lipid aggregation on the basis of interactions of small unilamellar vesicles of lecithin-cholesterol with bile salts as the latter's concentrations were varied from below to well above the critical micellar concentration. With submicellar bile salt concentrations likely to be found within hepatocytes, vesicle structures are not appreciably altered. However, perimicellar bile salt concentrations possibly occurring in canaliculi and bile ductules induce the formation of a hexagonal rodlike phase. On further increases in bile salt concentration, the hexagonal rods (formed from lecithin-rich and cholesterol-poor vesicles) are dissolved into mixed micelles as bile salt concentrations exceed their critical micellar concentrations. In slightly cholesterol-"supersaturated" biles, the rapid dissolution of this intermediate phase results in the formation of cholesterol-supersaturated mixed micelles that, in time, give rise to a new population of cholesterol-rich vesicles that coexist with saturated micelles.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Behavior of cholesterol and spin-labeled cholestane in model bile systems studied by electron spin resonance and synchrotron x-ray.

    PubMed Central

    Sömjen, G. J.; Lipka, G.; Schulthess, G.; Koch, M. H.; Wachtel, E.; Gilat, T.; Hauser, H.

    1995-01-01

    The behavior of mixed bile salt micelles consisting of sodium taurocholate, egg phosphatidylcholine, and cholesterol has been studied by ESR spin labeling and synchrotron x-ray scattering. Consistent with published phase diagrams, pure and mixed bile salt micelles have a limited capacity to incorporate and, hence, solubilize cholesterol. Excess cholesterol crystallizes out, a process that is readily detected both by ESR spin labeling using 3-doxyl-5 alpha-cholestane as a probe for cholesterol and synchrotron x-ray scattering. Both methods yield entirely consistent results. The crystallization of cholesterol from mixed bile salt micelles is indicated by the appearance of a magnetically dilute powder spectrum that is readily detected by visual inspection of the ESR spectra. Both the absence of Heissenberg spin exchange and the observation of a magnetically dilute powder spectrum provide evidence for the spin label co-crystallizing with cholesterol. In mixed bile salt micelles containing egg phosphatidylcholine, the solubility of cholesterol is increased as detected by both methods. With increasing content of phosphatidylcholine and increasing mole ratio cholesterol/phosphatidylcholine, the anisotropy of motion of the spin probe increases. The spin label 3-doxyl-5 alpha-cholestane is a useful substitute for cholesterol provided that it is used in dilute mixtures with excess cholesterol: the cholesterol/spin label mole ratio in these mixtures should be greater than 100. Despite the structural similarity between the two compounds, there are still significant differences in their physico-chemical properties. These differences come to the fore when cholesterol is totally replaced by the spin-label: 3-doxyl-5a-cholestane is significantly less soluble in bile salt and mixed bile salt micelles than cholesterol and, in contrast with cholesterol, it interacts only very weakly, if at all,with phosphatidylcholine. The potential of the ESR method for detecting cholesterol crystal

  13. Antiproliferation and apoptosis induced by tamoxifen in human bile duct carcinoma QBC939 cells via upregulated p53 expression

    SciTech Connect

    Han, Peng; Kang, Jin-He; Li, Hua-Liang; Hu, Su-Xian; Lian, Hui-Hui; Qiu, Ping-Ping; Zhang, Jian; Li, Wen-Gang; Chen, Qing-Xi

    2009-07-24

    Tamoxifen (TAM) is a nonsteroidal antiestrogen that has been used in the treatment of breast cancer for over 30 years. Recently, it was shown that TAM also has efficacy on gastrointestinal neoplasms such as hepatocarcinoma and pancreatic carcinoma, and that the chemopreventive activities of TAM might be due to its abilities to inhibit cell growth and induce apoptosis. In the present study, we investigated the effects of tamoxifen on growth and apoptosis in the human bile duct carcinoma (BDC) cell line QBC939 using MTT assay, inverted microscopy, fluorescence microscopy, transmission electron microscopy, classic DNA fragmentation agarose gel electrophoresis assay, PI single- and FITC/PI double-staining flow cytometry, and Western blotting. Our data revealed that TAM could significantly inhibit growth and induce apoptosis in QBC939 cells. Increased expression of p53 was observed in TAM-treated cells, indicating that p53 might play an important role in TAM-induced apoptosis in QBC939 cells. These results provide significant insight into the anticarcinogenic action of TAM on BDC.

  14. Bile acid signaling through FXR induces intracellular adhesion molecule-1 expression in mouse liver and human hepatocytes.

    PubMed

    Qin, Pu; Borges-Marcucci, Lisa A; Evans, Mark J; Harnish, Douglas C

    2005-08-01

    Previous studies have demonstrated a dramatic induction of inflammatory gene expression in livers from mice fed a high-fat, high-cholesterol diet containing cholate after 3-5 wk. To determine the contribution of cholate in mediating these inductions, C57BL/6 mice were fed a chow diet supplemented with increasing concentrations of cholic acid (CA) for 5 days. A dose-dependent induction in the hepatic levels of TNF-alpha, VCAM-1, ICAM-1, and SAA-2 mRNA were observed. As positive controls, a dose-dependent repression of cholesterol 7alpha-hydroxylase and a dose-dependent induction of small heterodimer partner (SHP) expression were also observed, suggesting that farnesoid X receptor (FXR) was activated. In addition, ICAM-1 and SHP mRNA levels were also induced in primary human hepatocytes when treated with chenodeoxycholic acid or GW4064, a FXR-selective agonist. The involvement of FXR in CA-induced inflammatory gene expression was further investigated in the human hepatic cell line HepG2. Both ICAM-1 and SHP expression were induced in a dose- and time-dependent manner by treatment with the FXR-selective agonist GW4064. Moreover, the induction of ICAM-1 by GW4064 was inhibited by the FXR antagonist guggulsterone or with transfection of FXR siRNA. Finally, the activity of FXR was mapped to a retinoic acid response element (RARE) site containing an imbedded farnesoid X response element (FXRE) on the human ICAM-1 promoter and FXR and retinoid X receptor were demonstrated to bind to this site. Finally, FXR-mediated activation of ICAM-1 could be further enhanced by TNF-alpha cotreatment in hepatocytes, suggesting a potential cooperation between cytokine and bile acid-signaling pathways during hepatic inflammatory events.

  15. Denatured globular protein and bile salt-coated nanoparticles for poorly water-soluble drugs: Penetration across the intestinal epithelial barrier into the circulation system and enhanced oral bioavailability.

    PubMed

    He, Wei; Yang, Ke; Fan, Lifang; Lv, Yaqi; Jin, Zhu; Zhu, Shumin; Qin, Chao; Wang, Yiao; Yin, Lifang

    2015-11-10

    Oral drug delivery is the most preferred route for patients; however, the low solubility of drugs and the resultant poor absorption compromise the benefits of oral administration. On the other hand, for years, the overwhelmingly accepted mechanism for enhanced oral absorption using lipid nanocarriers was based on the process of lipid digestion and drug solubilization in the small intestine. Few reports indicated that other bypass pathways are involved in drug absorption in the gastrointestinal tract (GIT) for oral delivery of nanocarriers. Herein, we report a new nanoemulsion system with a denatured globular protein with a diameter of 30 nm, soybean protein isolates (SPI), and bile salt as emulsifiers, aiming to enhance the absorption of insoluble drugs and explore other pathways for absorption. A BCS class II drug, fenofibrate (FB), was used as the model drug. The SPI and bile salt-coated Ns with a diameter of approximately 150 nm were prepared via a high-pressure homogenizing procedure. Interestingly, the present Ns could be converted to solid dosage form using fluid-bed coating technology, maintaining a nanoscale size. Most importantly, in a model of in situ rat intestinal perfusion, Ns could penetrate across the intestinal epithelial barrier into the systemic circulation and then obtain biodistribution into other tissues. In addition, Ns significantly improved FB oral absorption, exhibited as a greater than 2- and 2.5-fold increase in Cmax and AUC0-t, respectively, compared to the suspension formulation. Overall, the present Ns are promising nanocarriers for the oral delivery of insoluble drugs, and the penetration of intact Ns across the GIT barrier into systemic circulation may be a new strategy for improved drug absorption with the use of nanocarriers.

  16. Bile secretion in rats with indomethacin-induced intestinal inflammation.

    PubMed

    Yamada, T; Hoshino, M; Hayakawa, T; Kamiya, Y; Ohhara, H; Mizuno, K; Yamada, H; Nakazawa, T; Inagaki, T; Uchida, A; Miyaji, M; Takeuchi, T

    1996-05-01

    The objective of this study was to characterize the bile secretion, including the composition of biliary bile acids, bile salt pool size, and transcytotic vesicle transport, in a rat model of subacute intestinal inflammation induced by indomethacin. Indomethacin treatment significantly decreased bile acid-independent bile flow and biliary secretion of bile acid and cholesterol, while increasing biliary phospholipid output in vivo. Although indomethacin treatment did not change the bile salt pool size in vivo, alpha- and beta-muricholic acids were significantly deceased and hyodeoxycholic and deoxycholic acids were increased in bile. Bile flow and the transport maximum of taurocholate did not decrease, and biliary horseradish peroxidase output was significantly enhanced in isolated perfused livers from indomethacin-treated rats. Endotoxin in the portal blood was significantly increased in rats treated with indomethacin. Clindamycin slightly reduced intestinal inflammation but significantly prevented decreases in bile flow, bile acid output, and transport maximum of taurocholate. We conclude that, although biliary secretory function was apparently decreased in vivo, that of hepatocyte function was maintained in this model.

  17. Binding of bile acids by pastry products containing bioactive substances during in vitro digestion.

    PubMed

    Dziedzic, Krzysztof; Górecka, Danuta; Szwengiel, Artur; Smoczyńska, Paulina; Czaczyk, Katarzyna; Komolka, Patrycja

    2015-03-01

    The modern day consumer tends to choose products with health enhancing properties, enriched in bioactive substances. One such bioactive food component is dietary fibre, which shows a number of physiological properties including the binding of bile acids. Dietary fibre should be contained in everyday, easily accessible food products. Therefore, the aim of this study was to determine sorption capacities of primary bile acid (cholic acid - CA) and secondary bile acids (deoxycholic - DCA and lithocholic acids - LCA) by muffins (BM) and cookies (BC) with bioactive substances and control muffins (CM) and cookies (CC) in two sections of the in vitro gastrointestinal tract. Variations in gut flora were also analysed in the process of in vitro digestion of pastry products in a bioreactor. Enzymes: pepsin, pancreatin and bile salts: cholic acid, deoxycholic acid and lithocholic acid were added to the culture. Faecal bacteria, isolated from human large intestine, were added in the section of large intestine. The influence of dietary fibre content in cookies and concentration of bile acids in two stages of digestion were analysed. Generally, pastry goods with bioactive substances were characterized by a higher content of total fibre compared with the control samples. These products also differ in the profile of dietary fibre fractions. Principal Component Analysis (PCA) showed that the bile acid profile after two stages of digestion depends on the quality and quantity of fibre. The bile acid profile after digestion of BM and BC forms one cluster, and with the CM and CC forms a separate cluster. High concentration of H (hemicellulose) is positively correlated with LCA (low binding effect) and negatively correlated with CA and DCA contents. The relative content of bile acids in the second stage of digestion was in some cases above the content in the control sample, particularly LCA. This means that the bacteria introduced in the 2nd stage of digestion synthesize the LCA.

  18. Structural and Functional Characterization of BaiA, An Enzyme Involved in Secondary Bile Acid Synthesis in Human Gut Microbe

    PubMed Central

    Bhowmik, Shiva; Jones, David H.; Chiu, Hsien-Po; Park, In-Hee; Chiu, Hsiu-Ju; Axelrod, Herbert L.; Farr, Carol L.; Tien, Henry J.; Agarwalla, Sanjay; Lesley, Scott A.

    2014-01-01

    Despite significant influence of secondary bile acids on human health and disease, limited structural and biochemical information is available for the key gut microbial enzymes catalyzing its synthesis. Herein, we report apo- and co-factor bound crystal structures of BaiA2, a short chain dehydrogenase/reductase from Clostridium scindens VPI 12708 that represent the first protein structure of this pathway. The structures elucidated the basis of co-factor specificity and mechanism of proton relay. A conformational restriction involving Glu42 located in the co-factor binding site seems crucial in determining co-factor specificity. Limited flexibility of Glu42 results in imminent steric and electrostatic hindrance with 2′-phosphate group of NADP(H). Consistent with crystal structures, steady-state kinetic characterization performed with both BaiA2 and BaiA1, a close homolog with 92% sequence identity, revealed specificity constant (kcat/KM) of NADP+ at least an order of magnitude lower than NAD+. Substitution of Glu42 with Ala improved specificity towards NADP+ by 10- fold compared to wild type. The co-factor bound structure uncovered a novel nicotinamide-hydroxyl ion (NAD+-OH−) adduct contraposing previously reported adducts. The OH− of the adduct in BaiA2 is distal to C4 atom of nicotinamide and proximal to 2′-hydroxyl group of the ribose moiety. Moreover, it is located at intermediary distances between terminal functional groups of active site residues Tyr157 (2.7 Å) and Lys161 (4.5 Å). Based on these observations we propose an involvement of NAD+-OH− adduct in proton relay instead of hydride transfer as noted for previous adducts. PMID:23836456

  19. Effect of Maillard Reacted Peptides on Human Salt Taste and the Amiloride-Insensitive Salt Taste Receptor (TRPV1t)

    PubMed Central

    Katsumata, Tadayoshi; Nakakuki, Hiroko; Tokunaga, Chikara; Fujii, Noboru; Egi, Makoto; Phan, Tam-Hao T.; Mummalaneni, Shobha; DeSimone, John A.

    2008-01-01

    Maillard reacted peptides (MRPs) were synthesized by conjugating a peptide fraction (1000–5000 Da) purified from soy protein hydrolyzate with galacturonic acid, glucosamine, xylose, fructose, or glucose. The effect of MRPs was investigated on human salt taste and on the chorda tympani (CT) taste nerve responses to NaCl in Sprague–Dawley rats, wild-type, and transient receptor potential vanilloid 1 (TRPV1) knockout mice. MRPs produced a biphasic effect on human salt taste perception and on the CT responses in rats and wild-type mice in the presence of NaCl + benzamil (Bz, a blocker of epithelial Na+ channels), enhancing the NaCl response at low concentrations and suppressing it at high concentrations. The effectiveness of MRPs as salt taste enhancers varied with the conjugated sugar moiety: galacturonic acid = glucosamine > xylose > fructose > glucose. The concentrations at which MRPs enhanced human salt taste were significantly lower than the concentrations of MRPs that produced increase in the NaCl CT response. Elevated temperature, resiniferatoxin, capsaicin, and ethanol produced additive effects on the NaCl CT responses in the presence of MRPs. Elevated temperature and ethanol also enhanced human salt taste perception. N-(3-methoxyphenyl)-4-chlorocinnamid (a blocker of TRPV1t) inhibited the Bz-insensitive NaCl CT responses in the absence and presence of MRPs. TRPV1 knockout mice demonstrated no Bz-insensitive NaCl CT response in the absence or presence of MRPs. The results suggest that MRPs modulate human salt taste and the NaCl + Bz CT responses by interacting with TRPV1t. PMID:18603652

  20. Mueller-matrix invariants of optical anisotropy of the bile polycrystalline films in the diagnosis of human liver pathologies

    NASA Astrophysics Data System (ADS)

    Ushenko, V. O.; Prysyazhnyuk, V. P.; Dubolazov, O. V.; Savich, O. V.; Novakovska, O. Y.; Olar, O. V.

    2015-09-01

    The model of Mueller-matrix description of mechanisms of optical anisotropy typical for polycrystalline films of bile - optical activity, birefringence, as well as linear and circular dichroism - is suggested. Within the statistical analysis of such distributions the objective criteria of differentiation of films of bile from the dead you people different times were determined. From the point of view of probative medicine the operational characteristics (sensitivity, specificity and accuracy) of the method of Muellermatrix reconstruction of optical anisotropy parameters were found and its efficiency in another task - diagnostics of diseases of internal organs of rats was demonstrated.

  1. THE EFFECT OF BILE DUCT LIGATION AND BILE DIVERSION ON FK506 PHARMACOKINETICS IN DOGS1

    PubMed Central

    Furukawa, Hiroyoki; Imventarza, Oscar; Venkataramanan, Raman; Suzuki, Masatoshi; Zhu, Yue; Warty, Vijay S.; Fung, John; Todo, Satoru; Starzl, Thomas E.

    2011-01-01

    Mongrel or beagle dogs were submitted to bile duct ligation, or to extraenteric biliary diversion by means of choledochoureterostomy. The kinetics of intravenously administered FK506 was not changed from control status two weeks after bile duct ligation, but the bioavailability of orally administered FK506 was nearly quadrupled. Following oral administration, the absorption of FK508 was highly variable. The results indicate that in dogs FK506 is absorbed from the intestine just as efficiently in the absence of enteric bile and in presence of exogenous bile salt supplement when compared with its absorption in presence of normal bile drainage. These findings with FK506 are different from those with cyclosporine after biliary obstruction or diversion and will have important practical as well as experimental ramifications. PMID:1373531

  2. Synthesis and in vitro evaluation of gabapentin prodrugs that target the human apical sodium-dependent bile acid transporter (hASBT).

    PubMed

    Rais, Rana; Fletcher, Steven; Polli, James E

    2011-03-01

    Gabapentin is a zwitterionic drug that exhibits low and variable oral absorption at therapeutic doses. The human apical sodium-dependent bile acid transporter (hASBT; SLC10A2) is a potential prodrug target to increase oral drug absorption. The objective was to evaluate several bile acid conjugates of gabapentin as potential prodrugs that target hASBT. Five analogues were synthesized and varied in ionic nature and the presence or absence of glutamic acid linker between the bile acid and drug. Analogues were evaluated for their inhibition and uptake properties using stably transfected hASBT-MDCK cells. The two monoanionic conjugates were potent hASBT substrates, with high affinity (K(m) of 16.3 and 5.99 μM) and high capacity (V(max) of 0.656 and 0.842 pmol/cm(2) /s). The dianionic conjugate inhibited hASBT with moderate potency but was not a substrate. The two monoanionic conjugates were catalytically degraded in Caco-2 homogenate and rat liver microsomes. Each yielded gabapentin from prodrug. These two conjugates are novel prodrugs of gabapentin and illustrate prodrugs that can be designed to target hASBT.

  3. Properties Related to Bile as Viewed in Makhzan ol-Adviya

    PubMed Central

    Mosaffa-Jahromi, Maryam

    2016-01-01

    Background: The human body has simple and compound organs that obtain their nourishment through four humors. One of them is bile (yellow bile). According to Iranian traditional medicine (ITM), there are various kinds of natural medicines with their specific mechanisms of action affecting on bile in the human body. Hakim Aghili Shirazi (18th century), one of the great scholars in ITM field, introduced all types of natural medicines influencing bile in his valuable book written in Persian, “Makhzan-ul-Adwiah”, about single herbal medicines (mofradat). The aim of this review article was to introduce all types of natural medicines influencing bile in the human body. Methods: The classification of natural medicines influencing bile was studied in this article as viewed by Hakim Aghili Shirazi in Makhzan-ul-Adwiah. Results: Reviewing Makhzan-ul-Adwiah, this natural influencing bile is defined in ten categories. These are Haabes-e Safra (obstructive of bile), Daafe-e Safra (expellant of bile), Raafe-e Safra (resolver of bile), Ghaate-e Safra (stopper of bile), Ghaame-e Safra (suppressant of bile), Kaasere-e Safra (fractionating of bile), Mohregh-e Safra (burner of bile), Moder-e Safra (bile diuretic), Mosaken-e Safra (bile reliever), and Mos’hel-e Safra (bile laxative). Conclusion: Each group has a specific function and mechanism on bile. Recognition of the precise mechanisms of these natural medicines is necessary to prescribe a suitable remedy for bilious diseases by traditional medicine specialists. PMID:27516682

  4. Metastable and equilibrium phase diagrams of unconjugated bilirubin IXα as functions of pH in model bile systems: Implications for pigment gallstone formation.

    PubMed

    Berman, Marvin D; Carey, Martin C

    2015-01-01

    Metastable and equilibrium phase diagrams for unconjugated bilirubin IXα (UCB) in bile are yet to be determined for understanding the physical chemistry of pigment gallstone formation. Also, UCB is a molecule of considerable biomedical importance because it is a potent antioxidant and an inhibitor of atherogenesis. We employed principally a titrimetric approach to obtain metastable and equilibrium UCB solubilities in model bile systems composed of taurine-conjugated bile salts, egg yolk lecithin (mixed long-chain phosphatidylcholines), and cholesterol as functions of total lipid concentration, biliary pH values, and CaCl2 plus NaCl concentrations. Metastable and equilibrium precipitation pH values were obtained, and average pKa values of the two carboxyl groups of UCB were calculated. Added lecithin and increased temperature decreased UCB solubility markedly, whereas increases in bile salt concentrations and molar levels of urea augmented solubility. A wide range of NaCl and cholesterol concentrations resulted in no specific effects, whereas added CaCl2 produced large decreases in UCB solubilities at alkaline pH values only. UV-visible absorption spectra were consistent with both hydrophobic and hydrophilic interactions between UCB and bile salts that were strongly influenced by pH. Reliable literature values for UCB compositions of native gallbladder biles revealed that biles from hemolytic mice and humans with black pigment gallstones are markedly supersaturated with UCB and exhibit more acidic pH values, whereas biles from nonstone control animals and patients with cholesterol gallstone are unsaturated with UCB.

  5. Novel, major 2α- and 2β-hydroxy bile alcohols and bile acids in the bile of Arapaima gigas, a large South American river fish.

    PubMed

    Sato née Okihara, Rika; Saito, Tetsuya; Ogata, Hiroaki; Nakane, Naoya; Namegawa, Kazunari; Sekiguchi, Shoutaro; Omura, Kaoru; Kurabuchi, Satoshi; Mitamura, Kuniko; Ikegawa, Shigeo; Raines, Jan; Hagey, Lee R; Hofmann, Alan F; Iida, Takashi

    2016-03-01

    Bile alcohols and bile acids from gallbladder bile of the Arapaima gigas, a large South American freshwater fish, were isolated by reversed-phase high-performance liquid chromatography. The structures of the major isolated compounds were determined by electrospray-tandem mass spectrometry and nuclear magnetic resonance using (1)H- and (13)C-NMR spectra. The novel bile salts identified were six variants of 2-hydroxy bile acids and bile alcohols in the 5α- and 5β-series, with 29% of all compounds having hydroxylation at C-2. Three C27 bile alcohols were present (as ester sulfates): (24ξ,25ξ)-5α-cholestan-2α,3α,7α,12α,24,26-hexol; (25ξ)-5β-cholestan-2β,3α,7α,12α,26,27-hexol, and (25ξ)-5α-cholestan-2α,3α,7α,12α,26,27-hexol. A single C27 bile acid was identified: (25ξ)-2α,3α,7α,12α-tetrahydroxy-5α-cholestan-26-oic acid, present as its taurine conjugate. Two novel C24 bile acids were identified: the 2α-hydroxy derivative of allochenodeoxycholic acid and the 2β-hydroxy derivative of cholic acid, both occurring as taurine conjugates. These studies extend previous work in establishing the natural occurrence of novel 2α- and 2β-hydroxy-C24 and C27 bile acids as well as C27 bile alcohols in both the normal (5β) as well as the (5α) "allo" A/B-ring juncture. The bile salt profile of A. gigas appears to be unique among vertebrates. PMID:26768415

  6. Metabolism of [2-14C]p-hydroxyphenyl acetic acid in rat, monkey and human hepatocytes and in bile-duct cannulated rats.

    PubMed

    Zhou, Lian; Liu-Kreyche, Peggy; Iyer, Ramaswamy A

    2011-04-01

    We determined the metabolism of [2-(14)C]p-hydroxyphenyl acetic acid (p-HPA) in rat (male, Sprague-Dawley), monkey (male, Cynomolgus), and human (male, Caucasian) hepatocytes, and in bile-duct cannulated (BDC) rats (male, Sprague-Dawley). Unchanged p-HPA ranged from 87.0 to 92.6% of the total radioactivity (TRA) in the extracts of rat, monkey, and human hepatocytes. Metabolites M1 (a glucuronide conjugate of p-HPA) and M2 (a glycine conjugate of p-HPA) were detected, accounting for 1-4% of TRA. After an oral dose of [2-(14)C]p-HPA to BDC rats, p-HPA-related components was predominantly excreted in urine, accounting for 83% of the dose. Bile excretion was limited, accounting for only 1.5% of the dose. Unchanged p-HPA was the predominant radioactivity in plasma (84.6% of the TRA in 1-h pooled plasma) and urine (69.6% of the dose). Metabolites M1, M2, and M3 (a glucuronide of p-HPA) were all detected in plasma, urine, and bile as minor components. In summary, p-HPA was not metabolized extensively in rat, monkey, and human hepatocytes. In rats, absorption and elimination of p-HPA were nearly complete with urinary excretion of the unchanged p-HPA as the predominant route of elimination after oral dosing. No oxidative metabolites were detected, suggesting a minimal role for P450 enzymes in its overall metabolic clearance. Therefore, p-HPA has a low potential for drug-drug interactions mediated by the concomitant inhibitors and inducers of P450 enzymes.

  7. The physical chemistry of cholesterol solubility in bile. Relationship to gallstone formation and dissolution in man.

    PubMed Central

    Carey, M C; Small, D M

    1978-01-01

    We determined the maximum solubilities of cholesterol in aqueous conjugated bile salt-egg lecithin-cholesterol systems as a function of several physical-chemical variables including those of physiological importance employing phase equilibria techniques. Equilibration rates are influenced by time and the method of sample preparation in that metastable supersaturation is readily induced at high bile salt: lecithin ratios, and equilibrium saturation by dissolution is achieved sluggisly at low bile salt:lecithin ratios. Equilibrium values for cholesterol saturation vary with the bile salt species, bile salt: lecithin ratio, temperature, ionic strength, and, in particular, with the total concentration of biliary lipids. Within physiological bile salt:lecithin ratios at 37 degreesC the influence of bile salt type and ionic strength is small, whereas the effects of bile salt:lecithin ratio and the total lipid concentration are major factors. We plotted on triangular coordinates a family of cholesterol solubility curves for each total lipid concentration (0.30--30 g/dl) and computed fifth-degree polynomial equations for each curve. With both the curves and the polynomial equations the "per cent cholesterol saturation" of fasting gallbladder and hepatic biles from patients with and without gallstones was calculated and both methods gave similar values. These results deomonstrate that by employing cholesterol saturation values appropriate to the total lipid concentration (range 0.2--24.9 g/dl) of individual biles, all cholesterol stone patients have supersaturated gallbladder biles, (mean, 132% [normal weight individuals], and 199% [morbidly obese individuals]). With controls and pigment stone patients the mean values were 95 and 98%, respectively, and in both approximately 50% of biles were supersaturated. Fasting hepatic biles were significantly more supersaturated than gallbladder biles (means 228--273%). Cholesterol monohydrate crystals were found in the majority of

  8. Effect of organo and inorganic lithium salt on human blood plasma glutathione- A comparative study.

    PubMed

    Ullah, Hashmat; Khan, Muhammad Farid; Jan, Syed Umer; Hashmat, Farwa

    2016-03-01

    Investigation of toxicological effect of various metals is the field of interest for toxicological scientists since four to five decades and especially the toxicological effect of those drugs containing metals and there use is common because there is no other choice except to use these metal containing drugs. Inorganic as well as organic salts of lithium are commonly used in prophylaxis and treatments of many psychiatric disorders. The aim of the present study was to see the difference between the effect of organic and inorganic salt of lithium commonly used in psychiatric disorders on the GSH of human blood plasma. It is the scientific fact that ionic dissociation of organic and inorganic salts of any metal is always quite different hence to prove this fact, the effect of lithium citrate (organic salt of lithium) and lithium carbonate (inorganic salt of lithium) was investigated on human blood plasma GSH to find the difference between the effect of two. Ellman's method was used for the quantification of glutathione contents in plasma. It was found that lithium citrate decrease plasma GSH contents less than lithium carbonate indicating that organic salts of lithium are safe than inorganic salts of lithium when are used in psychiatric disorders. Further to analyze the effect of organic and inorganic salt of lithium on blood plasma GSH with the increase in incubation time was also evaluated and was found that both concentration and time dependent effect of organic salt of lithium shows that this salt has decreased plasma GSH contents of human blood less than inorganic salt of lithium either by promoting oxidation of GSH into GSSG or by lithium glutathione complex formation. These results suggest the physicians that the use of organic lithium salts is much safer than inorganic salts of lithium in terms of depletion of blood plasma GSH contents. PMID:27087067

  9. Identification and differentiation of bear bile used in medicinal products in Taiwan.

    PubMed

    Lin, D L; Chang, H C; Chang, C P; Chen, C Y

    1997-09-01

    One hundred eighty-three suspect bear bile used in medicinal products, collected in Taiwan as gall bladders or dried powder forms, were analyzed using FTIR, HPTLC, and HPLC techniques to identify whether they are indeed bear bile. Those confirmed were further examined to determine whether the observed analytical parameters can be reliably used for source inference, i.e., differentiating products among North American black bear, farmed Asiatic black bear, polar bear, etc. Our data suggested that North American and polar bears contain a higher concentration of TC (relative to TUDC and TCDC), whereas the relative concentration of TC in Asiatic bears (wild or farmed) is much lower. Thus, the relative concentration of TC can potentially be used for differentiating Asiatic bear bile from North American and polar bear products, but it cannot be used for the differentiation of wild and farmed bear bile as suggested in an earlier report by Espinoza et al. The origin of the 183 samples analyzed were found to be as follows: 118 (64%), bile salts, or gall bladders were of domestic pig; 56 (31%), bile products of Asiatic bear; 4 (2.2%), Asiatic bear mixed with pig bile salts; 3 (1.6%) goat gall bladders; 1 (0.55%) water buffalo bile salts; and 1 (0.55%), pig bile salts mixed with water buffalo bile salts. PMID:9304828

  10. Identification and differentiation of bear bile used in medicinal products in Taiwan.

    PubMed

    Lin, D L; Chang, H C; Chang, C P; Chen, C Y

    1997-09-01

    One hundred eighty-three suspect bear bile used in medicinal products, collected in Taiwan as gall bladders or dried powder forms, were analyzed using FTIR, HPTLC, and HPLC techniques to identify whether they are indeed bear bile. Those confirmed were further examined to determine whether the observed analytical parameters can be reliably used for source inference, i.e., differentiating products among North American black bear, farmed Asiatic black bear, polar bear, etc. Our data suggested that North American and polar bears contain a higher concentration of TC (relative to TUDC and TCDC), whereas the relative concentration of TC in Asiatic bears (wild or farmed) is much lower. Thus, the relative concentration of TC can potentially be used for differentiating Asiatic bear bile from North American and polar bear products, but it cannot be used for the differentiation of wild and farmed bear bile as suggested in an earlier report by Espinoza et al. The origin of the 183 samples analyzed were found to be as follows: 118 (64%), bile salts, or gall bladders were of domestic pig; 56 (31%), bile products of Asiatic bear; 4 (2.2%), Asiatic bear mixed with pig bile salts; 3 (1.6%) goat gall bladders; 1 (0.55%) water buffalo bile salts; and 1 (0.55%), pig bile salts mixed with water buffalo bile salts.

  11. Bile is essential for lipid assimilation in Leach's storm petrel, Oceanodroma leucorhoa.

    PubMed

    Place, A R

    1992-08-01

    A tritium-labeled glycerol triether was tested as a non-absorbable lipid marker for studies of neutral lipid absorption in normal and cholestryamine-induced steatorrhic chicks of Leach's storm petrel (Oceanodroma leucorhoa). Absorption of triacylglycerol and wax ester (96 +/- 4.2 and 94 +/- 2.1%, respectively) in normal chicks was indistinguishable. Absorption of neutral lipids decreased with increasing quantities of resin, and with the highest dosage (14% wt/wt) less than 30% of dietary lipids were assimilated. The concentration of bile salts (greater than 500 mM) in the gallbladder of Leach's storm petrel is among the highest recorded. The bile salts are predominantly taurine conjugates of chenodeoxycholate and cholate. Biliary cholesterol levels are within the range observed in humans although biliary phospholipid levels are lower and triglyceride levels are higher. Extensive retrograde movement of duodenal contents and biliary secretions to the gizzard and proventriculus were found. Although similarities in fat and bile salt assimilation exist between seabirds and mammals, there do exist differences that make non-polar lipid assimilation (i.e., wax esters) more efficient in seabirds. PMID:1510178

  12. Bile duct stricture

    MedlinePlus

    ... bile duct Damage or scarring after gallbladder removal Pancreatitis Primary sclerosing cholangitis ... your health care provider if symptoms recur after pancreatitis, cholecystectomy , or other biliary surgery.

  13. Preliminary analyses of scenarios for potential human interference for repositories in three salt formations

    SciTech Connect

    Not Available

    1985-10-01

    Preliminary analyses of scenarios for human interference with the performance of a radioactive waste repository in a deep salt formation are presented. The following scenarios are analyzed: (1) the U-Tube Connection Scenario involving multiple connections between the repository and the overlying aquifer system; (2) the Single Borehole Intrusion Scenario involving penetration of the repository by an exploratory borehole that simultaneously connects the repository with overlying and underlying aquifers; and (3) the Pressure Release Scenario involving inflow of water to saturate any void space in the repository prior to creep closure with subsequent release under near lithostatic pressures following creep closure. The methodology to evaluate repository performance in these scenarios is described and this methodology is applied to reference systems in three candidate formations: bedded salt in the Palo Duro Basin, Texas; bedded salt in the Paradox Basin, Utah; and the Richton Salt Dome, Mississippi, of the Gulf Coast Salt Dome Basin.

  14. Bile Acid Signaling in Metabolic Disease and Drug Therapy

    PubMed Central

    Li, Tiangang

    2014-01-01

    Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates hepatobiliary secretion of lipids, lipophilic metabolites, and xenobiotics. In the intestine, bile acids are essential for the absorption, transport, and metabolism of dietary fats and lipid-soluble vitamins. Extensive research in the last 2 decades has unveiled new functions of bile acids as signaling molecules and metabolic integrators. The bile acid–activated nuclear receptors farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, and G protein–coupled bile acid receptor play critical roles in the regulation of lipid, glucose, and energy metabolism, inflammation, and drug metabolism and detoxification. Bile acid synthesis exhibits a strong diurnal rhythm, which is entrained by fasting and refeeding as well as nutrient status and plays an important role for maintaining metabolic homeostasis. Recent research revealed an interaction of liver bile acids and gut microbiota in the regulation of liver metabolism. Circadian disturbance and altered gut microbiota contribute to the pathogenesis of liver diseases, inflammatory bowel diseases, nonalcoholic fatty liver disease, diabetes, and obesity. Bile acids and their derivatives are potential therapeutic agents for treating metabolic diseases of the liver. PMID:25073467

  15. Regulation of hepatic bile acid transporters Ntcp and Bsep expression

    PubMed Central

    Cheng, Xingguo; Buckley, David; Klaassen, Curtis D.

    2009-01-01

    Sodium-taurocholate cotransporting polypeptide (Ntcp) and bile salt export pump (Bsep) are two key transporters for hepatic bile acid uptake and excretion. Alterations in Ntcp and Bsep expression have been reported in pathophysiological conditions. In the present study, the effects of age, gender, and various chemicals on the regulation of these two transporters were characterized in mice. Ntcp and Bsep mRNA levels in mouse liver were low in the fetus, but increased to its highest expression at parturition. After birth, mouse Ntcp and Bsep mRNA decreased by more than 50%, and then gradually increased to adult levels by day 30. Expression of mouse Ntcp mRNA and protein exhibit higher levels in female than male livers, which is consistent with the trend of human NTCP mRNA expression between men and women. No gender difference exists in BSEP/Bsep expression in human and mouse livers. Hormone replacements conducted in gonadectomized, hypophysectomized, and lit/lit mice indicate that female-predominant Ntcp expression in mouse liver is due to the inhibitory effect of male-pattern GH secretion, but not sex hormones. Ntcp and Bsep expression are in general resistant to induction by a large battery of microsomal enzyme inducers. Administration of cholestyramine increased Ntcp, whereas chenodeoxycholic acid increased Bsep mRNA expression. In silico analysis indicates that female-predominant mouse and human Ntcp/NTCP expression may be due to GH. In conclusion, mouse Ntcp and Bsep are regulated by age, gender, cholestyramine, and bile acid, but resistant to induction by most microsomal enzyme inducers. PMID:17897632

  16. Estimated human health risks of disposing of nonhazardous oil field waste in salt caverns

    SciTech Connect

    Tomasko, D.; Elcock, D.; Veil, J.

    1997-09-01

    Argonne National Laboratory (ANL) has completed an evaluation of the possibility that adverse human health effects (carcinogenic and noncarcinogenic) could result from exposure to contaminants released from nonhazardous oil field wastes (NOW) disposed in domal salt caverns. In this assessment, several steps were used to evaluate potential human health risks: identifying potential contaminants of concern, determining how humans could be exposed to these contaminants, assessing the contaminants` toxicities, estimating contaminant intakes, and, finally, calculating human cancer and noncancer risks.

  17. Salmonella L-forms: formation in human bile in vitro and isolation culture from patients' gallbladder samples by a non-high osmotic isolation technique.

    PubMed

    Wang, D N; Wu, W J; Wang, T; Pan, Y Z; Tang, K L; She, X L; Ding, W J; Wang, H

    2015-05-01

    Bacterial L-forms have always been considered as osmotic-pressure-sensitive cell-wall-deficient bacteria and isolation culture of L-forms must use media with high osmotic pressure. However, isolation culture of stable L-forms formed in humans and animals is very difficult because they have adapted to the physiological osmotic pressure condition of the host. We use a non-high osmotic isolation technique to isolate stable L-forms of Salmonella Typhi and Salmonella Paratyphi A from bile-inducer cultures in vitro and from patients' gallbladder specimens. Multiplex PCR assay for Salmonella-specific genes and nucleotide sequencing are used to identify the Salmonella L-forms in stable L-form isolates. Using this method, we confirmed that Salmonella Paratyphi A and Salmonella Typhi cannot be isolated from bile-inducer cultures cultured for 6 h or 48 h, but the L-forms can be isolated from 1 h to 45 days. In the 524 gallbladder samples, the positive rate for bacterial forms was 19.7% and the positive rate for Salmonella spp. was 0.6% by routine bacteriological methods. The positive rate for bacterial L-forms was 75.4% using non-high osmotic isolation culture. In the L-form isolates, the positive rate of Salmonella invA gene was 3.1%. In these invA-positive L-form isolates, four were positive for the invA and flic-d genes of Salmonella Typhi, and ten were positive for the invA and flic-a genes of Salmonella Paratyphi A.

  18. Alteration of Bile Canalicular Enzymes in Cholestasis. A POSSIBLE CAUSE OF BILE SECRETORY FAILURE

    PubMed Central

    Simon, Francis R.; Arias, Irwin M.

    1973-01-01

    Bile secretory failure (cholestasis) may result from several possible mechanisms involved in bile secretion. We have examined the possibility that abnormalities in enzyme content, composition, and turnover of liver plasma membrane constituents are altered in cholestasis. Severe and mild cholestasis were produced by 5 days of bile duct ligation and ethinyl estradiol administration, respectively. Bile duct ligation but not ethinyl estradiol treatments was associated with elevations of the serum bilirubin level and 5′-nucleotidase activity. However, basal bile flow and bilirubin transport maximum (Tm) were significantly reduced after ethinyl estradiol treatment. Liver plasma membrane fractions rich in canalicular membranes were prepared from groups of rats in each of three categories; normal, after bile duct ligation, or ethinyl estradiol administration, and their respective controls. Electron microscopy and enzyme marker studies demonstrated plasma membrane fractions free of significant contamination. Plasma membrane fractions prepared from mild as well as severe cholestasis had increased alkaline phosphatase activity, and reduced 5′-nucleotidase and Mg2+-ATPase activities. Co2+-CMPase activity was unchanged. Kinetic analysis of 5′-nucleotidase and Mg2+-ATPase activities in plasma membrane fractions demonstrated reduced Vmaz (but unaltered Km). Reducted Vmaz was unrelated to addition in vitro of di-or trihydroxy bile salts or ethinyl estradiol and, therefore, suggests that reduced activities in cholestasis are due to decreased enzyme content. Cholestasis was not associated with changes in the synthesis or degradation rate of pulse-labeled plasma membrane proteins or alterations in the major protein bands separated on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Plasma membrane cholesterol, phospholipid, and neutral sugar content was unaltered, but sialic acid content was significantly increased in both forms of cholestasis. Alterations in

  19. Transcriptional regulation of human mucin MUC4 by bile acids in oesophageal cancer cells is promoter-dependent and involves activation of the phosphatidylinositol 3-kinase signalling pathway.

    PubMed Central

    Mariette, Christophe; Perrais, Michaël; Leteurtre, Emmanuelle; Jonckheere, Nicolas; Hémon, Brigitte; Pigny, Pascal; Batra, Surinder; Aubert, Jean-Pierre; Triboulet, Jean-Pierre; Van Seuningen, Isabelle

    2004-01-01

    Abnormal gastro-oesophageal reflux and bile acids have been linked to the presence of Barrett's oesophageal premalignant lesion associated with an increase in mucin-producing goblet cells and MUC4 mucin gene overexpression. However, the molecular mechanisms underlying the regulation of MUC4 by bile acids are unknown. Since total bile is a complex mixture, we undertook to identify which bile acids are responsible for MUC4 up-regulation by using a wide panel of bile acids and their conjugates. MUC4 apomucin expression was studied by immunohistochemistry both in patient biopsies and OE33 oesophageal cancer cell line. MUC4 mRNA levels and promoter regulation were studied by reverse transcriptase-PCR and transient transfection assays respectively. We show that among the bile acids tested, taurocholic, taurodeoxycholic, taurochenodeoxycholic and glycocholic acids and sodium glycocholate are strong activators of MUC4 expression and that this regulation occurs at the transcriptional level. By using specific pharmacological inhibitors of mitogen-activated protein kinase, phosphatidylinositol 3-kinase, protein kinase A and protein kinase C, we demonstrate that bile acid-mediated up-regulation of MUC4 is promoter-specific and mainly involves activation of phosphatidylinositol 3-kinase. This new mechanism of regulation of MUC4 mucin gene points out an important role for bile acids as key molecules in targeting MUC4 overexpression in early stages of oesophageal carcinogenesis. PMID:14583090

  20. Properties of salt-resistant lipase and lipoprotein lipase purified from human post-heparin plasma.

    PubMed Central

    Ostlund-Lindqvist, A M

    1979-01-01

    Lipoprotein lipase and salt-resistant lipase were isolated from human post-heparin plasma. The proteins of human post-plasma lipoprotein lipase and salt-resistant lipase were identified and demonstrated to be immunologically different. Significant differences between the two enzymes in their relative amino acid composition were demonstrated, which indicates that the two enzymes are different proteins. When analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the enzymes seemed to have monomer molecular weights similar to that of lipoprotein lipase purified from bovine milk. Images Fig. 1. Fig. 3. PMID:113002

  1. The nitrosated bile acid DNA lesion O6-carboxymethylguanine is a substrate for the human DNA repair protein O6-methylguanine-DNA methyltransferase

    PubMed Central

    Senthong, Pattama; Millington, Christopher L.; Wilkinson, Oliver J.; Marriott, Andrew S.; Watson, Amanda J.; Reamtong, Onrapak; Eyers, Claire E.; Williams, David M.; Margison, Geoffrey P.; Povey, Andrew C.

    2013-01-01

    The consumption of red meat is a risk factor in human colorectal cancer (CRC). One hypothesis is that red meat facilitates the nitrosation of bile acid conjugates and amino acids, which rapidly convert to DNA-damaging carcinogens. Indeed, the toxic and mutagenic DNA adduct O6-carboxymethylguanine (O6-CMG) is frequently present in human DNA, increases in abundance in people with high levels of dietary red meat and may therefore be a causative factor in CRC. Previous reports suggested that O6-CMG is not a substrate for the human version of the DNA damage reversal protein O6-methylguanine-DNA methyltransferase (MGMT), which protects against the genotoxic effects of other O6-alkylguanine lesions by removing alkyl groups from the O6-position. We now show that synthetic oligodeoxyribonucleotides containing the known MGMT substrate O6-methylguanine (O6-MeG) or O6-CMG effectively inactivate MGMT in vitro (IC50 0.93 and 1.8 nM, respectively). Inactivation involves the removal of the O6-alkyl group and its transfer to the active-site cysteine residue of MGMT. O6-CMG is therefore an MGMT substrate, and hence MGMT is likely to be a protective factor in CRC under conditions where O6-CMG is a potential causative agent. PMID:23335782

  2. Dynamic laser light scattering studies of the micelle to vesicle transition in model and native bile.

    PubMed

    Schurtenberger, P; Mazer, N A; Känzig, W

    1984-01-01

    Using quasielastic light scattering, we investigated the formation of vesicles produced spontaneously by diluting a mixed micellar solution of bile salt and lecithin beyond the micellar phase boundary. The vesicles were nearly monodisperse, and their size varied between 120 to 500 A depending upon the dilution conditions. A systematic study of the dependence of the vesicle size upon the bile salt and lecithin concentration was made and interpreted in terms of a simple equilibrium model. Likewise, the particle size distribution in native bile obtained from the dog was studied. A comparison of the dilution effect on native bile and on model bile of identical biliary lipid composition provides unambiguous evidence for micellar aggregates and the occurrence of a micelle to vesicle transition in native bile.

  3. Role of vesicle-mediated transport pathways in hepatocellular bile secretion.

    PubMed

    Crawford, J M

    1996-05-01

    Bile formation by hepatocytes involves the secretion of organic and inorganic solutes derived from a number of intracellular sources. Plasma-to-bile trafficking of bile salts and proteins, in particular, is a major route for solute movement through the hepatocyte. Intracellular vesicle trafficking is the primary pathway for delivery of plasma proteins to bile, via either fluid-phase or receptor-mediated endocytosis. In contrast, bile salts do not appear to traffic via vesicles. Rather, bile salts appear to promote the insertion of vesicles containing the apical transport proteins into the hepatocyte canalicular membrane. Lysosomal protein also is released into bile by fusion of vesicles or possibly of tubular lysosomes with the canalicular membrane. Structural phospholipid is presumably delivered to the canalicular membrane as part of vesicular traffic, but biliary phosphatidylcholine molecules are more likely delivered via binding to cytosolic transfer proteins. Cholesterol may be delivered either via cystolic proteins or via vesicular trafficking, the latter in conjunction with sphingomyelin recycling to and from the canalicular membrane. Lastly, the primary mechanism for phospholipid secretion into bile appears to be the budding of phospholipid vesicles from the exoplasmic hemileaflet of the hepatocyte canalicular membrane. Thus, vesicle-mediated pathways play a major role in a number of bile secretory mechanisms.

  4. Disulfide bridge regulates ligand-binding site selectivity in liver bile acid-binding proteins.

    PubMed

    Cogliati, Clelia; Tomaselli, Simona; Assfalg, Michael; Pedò, Massimo; Ferranti, Pasquale; Zetta, Lucia; Molinari, Henriette; Ragona, Laura

    2009-10-01

    Bile acid-binding proteins (BABPs) are cytosolic lipid chaperones that play central roles in driving bile flow, as well as in the adaptation to various pathological conditions, contributing to the maintenance of bile acid homeostasis and functional distribution within the cell. Understanding the mode of binding of bile acids with their cytoplasmic transporters is a key issue in providing a model for the mechanism of their transfer from the cytoplasm to the nucleus, for delivery to nuclear receptors. A number of factors have been shown to modulate bile salt selectivity, stoichiometry, and affinity of binding to BABPs, e.g. chemistry of the ligand, protein plasticity and, possibly, the formation of disulfide bridges. Here, the effects of the presence of a naturally occurring disulfide bridge on liver BABP ligand-binding properties and backbone dynamics have been investigated by NMR. Interestingly, the disulfide bridge does not modify the protein-binding stoichiometry, but has a key role in modulating recognition at both sites, inducing site selectivity for glycocholic and glycochenodeoxycholic acid. Protein conformational changes following the introduction of a disulfide bridge are small and located around the inner binding site, whereas significant changes in backbone motions are observed for several residues distributed over the entire protein, both in the apo form and in the holo form. Site selectivity appears, therefore, to be dependent on protein mobility rather than being governed by steric factors. The detected properties further establish a parallelism with the behaviour of human ileal BABP, substantiating the proposal that BABPs have parallel functions in hepatocytes and enterocytes. PMID:19754879

  5. Disulfide bridge regulates ligand-binding site selectivity in liver bile acid-binding proteins.

    PubMed

    Cogliati, Clelia; Tomaselli, Simona; Assfalg, Michael; Pedò, Massimo; Ferranti, Pasquale; Zetta, Lucia; Molinari, Henriette; Ragona, Laura

    2009-10-01

    Bile acid-binding proteins (BABPs) are cytosolic lipid chaperones that play central roles in driving bile flow, as well as in the adaptation to various pathological conditions, contributing to the maintenance of bile acid homeostasis and functional distribution within the cell. Understanding the mode of binding of bile acids with their cytoplasmic transporters is a key issue in providing a model for the mechanism of their transfer from the cytoplasm to the nucleus, for delivery to nuclear receptors. A number of factors have been shown to modulate bile salt selectivity, stoichiometry, and affinity of binding to BABPs, e.g. chemistry of the ligand, protein plasticity and, possibly, the formation of disulfide bridges. Here, the effects of the presence of a naturally occurring disulfide bridge on liver BABP ligand-binding properties and backbone dynamics have been investigated by NMR. Interestingly, the disulfide bridge does not modify the protein-binding stoichiometry, but has a key role in modulating recognition at both sites, inducing site selectivity for glycocholic and glycochenodeoxycholic acid. Protein conformational changes following the introduction of a disulfide bridge are small and located around the inner binding site, whereas significant changes in backbone motions are observed for several residues distributed over the entire protein, both in the apo form and in the holo form. Site selectivity appears, therefore, to be dependent on protein mobility rather than being governed by steric factors. The detected properties further establish a parallelism with the behaviour of human ileal BABP, substantiating the proposal that BABPs have parallel functions in hepatocytes and enterocytes.

  6. Bile acids reduce the apoptosis-inducing effects of sodium butyrate on human colon adenoma (AA/C1) cells: implications for colon carcinogenesis.

    PubMed

    McMillan, L; Butcher, S; Wallis, Y; Neoptolemos, J P; Lord, J M

    2000-06-24

    Butyrate is produced in the colon by fermentation of dietary fibre and induces apoptosis in colon adenoma and cancer cell lines, which may contribute to the protective effect of a high fibre diet against colorectal cancer (CRC). However, butyrate is present in the colon together with unconjugated bile acids, which are tumour promoters in the colon. We show here that bile acids deoxycholate (DCA) and chenodeoxycholate (CDCA), at levels present in the colon, gave a modest increase in cell proliferation and decreased spontaneous apoptosis in AA/C1 adenoma cells. Bile acids significantly inhibited the induction of apoptosis by butyrate in AA/C1 cells. However, the survival-inducing effects of bile acids on AA/C1 cells could be overcome by increasing the concentration of sodium butyrate. These results suggest that dysregulation of apoptosis in colonic epithelial cells by dietary factors is a key factor in the pathophysiology of CRC.

  7. Effects of dietary salt levels on monocytic cells and immune responses in healthy human subjects: a longitudinal study.

    PubMed

    Yi, Buqing; Titze, Jens; Rykova, Marina; Feuerecker, Matthias; Vassilieva, Galina; Nichiporuk, Igor; Schelling, Gustav; Morukov, Boris; Choukèr, Alexander

    2015-07-01

    Increasing evidence indicated that excess salt consumption can impose risks on human health and a reduction in daily salt intake from the current average of approximately 12 g/d to 5-6 g/d was suggested by public health authorities. The studies on mice have revealed that sodium chloride plays a role in the modulation of the immune system and a high-salt diet can promote tissue inflammation and autoimmune disease. However, translational evidence of dietary salt on human immunity is scarce. We used an experimental approach of fixing salt intake of healthy human subjects at 12, 9, and 6 g/d for months and examined the relationship between salt-intake levels and changes in the immune system. Blood samples were taken from the end point of each salt intake period. Immune phenotype changes were monitored through peripheral leukocyte phenotype analysis. We assessed immune function changes through the characterization of cytokine profiles in response to mitogen stimulation. The results showed that subjects on the high-salt diet of 12 g/d displayed a significantly higher number of immune cell monocytes compared with the same subjects on a lower-salt diet, and correlation test revealed a strong positive association between salt-intake levels and monocyte numbers. The decrease in salt intake was accompanied by reduced production of proinflammatory cytokines interleukin (IL)-6 and IL-23, along with enhanced producing ability of anti-inflammatory cytokine IL-10. These results suggest that in healthy humans high-salt diet has a potential to bring about excessive immune response, which can be damaging to immune homeostasis, and a reduction in habitual dietary salt intake may induce potentially beneficial immune alterations.

  8. Advances in understanding of bile acid diarrhea

    PubMed Central

    Camilleri, Michael

    2014-01-01

    Bile acids (BA) are actively reabsorbed in the terminal ileum by the apical Na+-dependent bile salt transporter. This review addresses the epidemiology, pathophysiology, diagnosis and treatment of BA diarrhea (BAD). BAD is typically caused by ileal resection or disease; 25–33% of patients with chronic functional diarrhea or irritable bowel syndrome-diarrhea (IBS-D) have BAD, possibly from deficiency in the ileal hormone, FGF-19, which normally provides feedback inhibition of BA synthesis. Diagnosis of BAD is typically based on reduced BA retention of radiolabeled BA (75SeHCAT), increased BA synthesis (serum C4) or increased fecal BA loss. In clinical practice, diagnosis is often based on response to BA sequestrants (e.g., cholestyramine or colesevelam). Diagnostic tests for BA malabsorption (BAM) need to be used more extensively in clinical practice. In the future, farnesoid X receptor agonists that stimulate ileal production of FGF-19 may be alternative treatments of BAD. PMID:24410472

  9. [Iatrogenic bile duct injuries].

    PubMed

    Ruiz Gómez, Francisco; Ramia Ángel, José Manuel; García-Parreño Jofré, Jorge; Figueras, Joan

    2010-10-01

    Bile duct injuries can be caused by different reasons, with Iatrogenic Bile Duct Injuries (IBDI) being the most common factor. IBDI is a complex situation produced in apparently healthy patients and is associated with a high rate of morbidity and a low rate of mortality. A multidisciplinary approach between surgeons, radiologist and endoscopist offers the best chances for an initial diagnosis, therapeutic options, management and follow up of complications for the patient. The aim of this review is to describe the current medical literature with reference to IBDI, and discuss our therapeutic algorithm.

  10. Salt handling in the distal nephron: lessons learned from inherited human disorders.

    PubMed

    Jeck, Nikola; Schlingmann, Karl P; Reinalter, Stephan C; Kömhoff, Martin; Peters, Melanie; Waldegger, Siegfried; Seyberth, Hannsjörg W

    2005-04-01

    The molecular basis of inherited salt-losing tubular disorders with secondary hypokalemia has become much clearer in the past two decades. Two distinct segments along the nephron turned out to be affected, the thick ascending limb of Henle's loop and the distal convoluted tubule, accounting for two major clinical phenotypes, hyperprostaglandin E syndrome and Bartter-Gitelman syndrome. To date, inactivating mutations have been detected in six different genes encoding for proteins involved in renal transepithelial salt transport. Careful examination of genetically defined patients ("human knockouts") allowed us to determine the individual role of a specific protein and its contribution to the overall process of renal salt reabsorption. The recent generation of several genetically engineered mouse models that are deficient in orthologous genes further enabled us to compare the human phenotype with the animal models, revealing some unexpected interspecies differences. As the first line treatment in hyperprostaglandin E syndrome includes cyclooxygenase inhibitors, we propose some hypotheses about the mysterious role of PGE(2) in the etiology of renal salt-losing disorders. PMID:15793031

  11. Digestion of phospholipids after secretion of bile into the duodenum changes the phase behavior of bile components.

    PubMed

    Birru, Woldeamanuel A; Warren, Dallas B; Ibrahim, Ahmed; Williams, Hywel D; Benameur, Hassan; Porter, Christopher J H; Chalmers, David K; Pouton, Colin W

    2014-08-01

    Bile components play a significant role in the absorption of dietary fat, by solubilizing the products of fat digestion. The absorption of poorly water-soluble drugs from the gastrointestinal tract is often enhanced by interaction with the pathways of fat digestion and absorption. These processes can enhance drug absorption. Thus, the phase behavior of bile components and digested lipids is of great interest to pharmaceutical scientists who seek to optimize drug solubilization in the gut lumen. This can be achieved by dosing drugs after food or preferably by formulating the drug in a lipid-based delivery system. Phase diagrams of bile salts, lecithin, and water have been available for many years, but here we investigate the association structures that occur in dilute aqueous solution, in concentrations that are present in the gut lumen. More importantly, we have compared these structures with those that would be expected to be present in the intestine soon after secretion of bile. Phosphatidylcholines are rapidly hydrolyzed by pancreatic enzymes to yield equimolar mixtures of their monoacyl equivalents and fatty acids. We constructed phase diagrams that model the association structures formed by the products of digestion of biliary phospholipids. The micelle-vesicle phase boundary was clearly identifiable by dynamic light scattering and nephelometry. These data indicate that a significantly higher molar ratio of lipid to bile salt is required to cause a transition to lamellar phase (i.e., liposomes in dilute solution). Mixed micelles of digested bile have a higher capacity for solubilization of lipids and fat digestion products and can be expected to have a different capacity to solubilize lipophilic drugs. We suggest that mixtures of lysolecithin, fatty acid, and bile salts are a better model of molecular associations in the gut lumen, and such mixtures could be used to better understand the interaction of drugs with the fat digestion and absorption pathway.

  12. Expression of colonization factor CS5 of enterotoxigenic Escherichia coli (ETEC) is enhanced in vivo and by the bile component Na glycocholate hydrate.

    PubMed

    Nicklasson, Matilda; Sjöling, Åsa; von Mentzer, Astrid; Qadri, Firdausi; Svennerholm, Ann-Mari

    2012-01-01

    Enterotoxigenic Escherichia coli (ETEC) is an important cause of acute watery diarrhoea in developing countries. Colonization factors (CFs) on the bacterial surface mediate adhesion to the small intestinal epithelium. Two of the most common CFs worldwide are coli surface antigens 5 and 6 (CS5, CS6). In this study we investigated the expression of CS5 and CS6 in vivo, and the effects of bile and sodium bicarbonate, present in the human gut, on the expression of CS5. Five CS5+CS6 ETEC isolates from adult Bangladeshi patients with acute diarrhoea were studied. The level of transcription from the CS5 operon was approximately 100-fold higher than from the CS6 operon in ETEC bacteria recovered directly from diarrhoeal stool without sub-culturing (in vivo). The glyco-conjugated primary bile salt sodium glycocholate hydrate (NaGCH) induced phenotypic expression of CS5 in a dose-dependent manner and caused a 100-fold up-regulation of CS5 mRNA levels; this is the first description of NaGCH as an enteropathogenic virulence inducer. The relative transcription levels from the CS5 and CS6 operons in the presence of bile or NaGCH in vitro were similar to those in vivo. Another bile salt, sodium deoxycholate (NaDC), previously reported to induce enteropathogenic virulence, also induced expression of CS5, whereas sodium bicarbonate did not.

  13. Expression of colonization factor CS5 of enterotoxigenic Escherichia coli (ETEC) is enhanced in vivo and by the bile component Na glycocholate hydrate.

    PubMed

    Nicklasson, Matilda; Sjöling, Åsa; von Mentzer, Astrid; Qadri, Firdausi; Svennerholm, Ann-Mari

    2012-01-01

    Enterotoxigenic Escherichia coli (ETEC) is an important cause of acute watery diarrhoea in developing countries. Colonization factors (CFs) on the bacterial surface mediate adhesion to the small intestinal epithelium. Two of the most common CFs worldwide are coli surface antigens 5 and 6 (CS5, CS6). In this study we investigated the expression of CS5 and CS6 in vivo, and the effects of bile and sodium bicarbonate, present in the human gut, on the expression of CS5. Five CS5+CS6 ETEC isolates from adult Bangladeshi patients with acute diarrhoea were studied. The level of transcription from the CS5 operon was approximately 100-fold higher than from the CS6 operon in ETEC bacteria recovered directly from diarrhoeal stool without sub-culturing (in vivo). The glyco-conjugated primary bile salt sodium glycocholate hydrate (NaGCH) induced phenotypic expression of CS5 in a dose-dependent manner and caused a 100-fold up-regulation of CS5 mRNA levels; this is the first description of NaGCH as an enteropathogenic virulence inducer. The relative transcription levels from the CS5 and CS6 operons in the presence of bile or NaGCH in vitro were similar to those in vivo. Another bile salt, sodium deoxycholate (NaDC), previously reported to induce enteropathogenic virulence, also induced expression of CS5, whereas sodium bicarbonate did not. PMID:22563407

  14. [Bile acids in the bile in diabetes mellitus].

    PubMed

    Slivka, O Ia; Zelinskiĭ, B A; Zelinskiĭ, S Ts

    1979-01-01

    Hepatic and gall bladder bile of healthy persons (8) and of patients with severe form of diabetes mellitus (17) was studied. Paer chromatography was applied for determination of cholic, chenodeoxycholic, deoxycholic bile acids and their conjugates with glycin and taurine. An absolute content and percentage of glycodeoxycholic and glycochenodeoxycholic bile acids were increased, and glycochenodeoxycholic acid content and taurates proportion were decreased in the gall bladder and hepatic bile of diabetic patients. The data obtained pointed to disturbed hepatic function in severe diabetes mellitus; it was expressed in suppression of bile acids synthesis and conjugation, and also in depression of transformation of deoxycholic into cholic acid.

  15. The bile acid composition of crane gallbladder bile

    USGS Publications Warehouse

    Serafin, J.A.

    1983-01-01

    1. 1. The biliary bile acids of the whooping crane (Grus americana) and the Florida sandhill crane (G. canadensis pratensis) have been examined. 2. 2. Cholic acid (CA), chenodeoxycholic acid (CDOCA) and lithocholic acid were found in bile from both species of these North American cranes. 3. 3. CDOCA and CA were the primary bile acids in both species, together constituting 70% or more of the bile acids by weight. 4. 4. The primary bile acids of cranes appear to be the same as those that have been identified in other avian species.

  16. The Effect of Oxygen on Bile Resistance in Listeria monocytogenes

    PubMed Central

    Wright, Morgan L; Pendarvis, Ken; Nanduri, Bindu; Edelmann, Mariola J; Jenkins, Haley N; Reddy, Joseph S; Wilson, Jessica G; Ding, Xuan; Broadway, Paul R; Ammari, Mais G; Paul, Oindrila; Roberts, Brandy; Donaldson, Janet R

    2016-01-01

    Listeria monocytogenes is a Gram-positive facultative anaerobe that is the causative agent of the disease listeriosis. The infectious ability of this bacterium is dependent upon resistance to stressors encountered within the gastrointestinal tract, including bile. Previous studies have indicated bile salt hydrolase activity increases under anaerobic conditions, suggesting anaerobic conditions influence stress responses. Therefore, the goal of this study was to determine if reduced oxygen availability increased bile resistance of L. monocytogenes. Four strains representing three serovars were evaluated for changes in viability and proteome expression following exposure to bile in aerobic or anaerobic conditions. Viability for F2365 (serovar 4b), EGD-e (serovar 1/2a), and 10403S (serovar 1/2a) increased following exposure to 10% porcine bile under anaerobic conditions (P < 0.05). However, HCC23 (serovar 4a) exhibited no difference (P > 0.05) in bile resistance between aerobic and anaerobic conditions, indicating that oxygen availability does not influence resistance in this strain. The proteomic analysis indicated F2365 and EGD-e had an increased expression of proteins associated with cell envelope and membrane bioenergetics under anaerobic conditions, including thioredoxin-disulfide reductase and cell division proteins. Interestingly, HCC23 had an increase in several dehydrogenases following exposure to bile under aerobic conditions, suggesting that the NADH:NAD+ is altered and may impact bile resistance. Variations were observed in the expression of the cell shape proteins between strains, which corresponded to morphological differences observed by scanning electron microscopy. These data indicate that oxygen availability influences bile resistance. Further research is needed to decipher how these changes in metabolism impact pathogenicity in vivo and also the impact that this has on susceptibility of a host to listeriosis. PMID:27274623

  17. Rate of steroid double-bond reduction catalysed by the human steroid 5β-reductase (AKR1D1) is sensitive to steroid structure: implications for steroid metabolism and bile acid synthesis.

    PubMed

    Jin, Yi; Chen, Mo; Penning, Trevor M

    2014-08-15

    Human AKR1D1 (steroid 5β-reductase/aldo-keto reductase 1D1) catalyses the stereospecific reduction of double bonds in Δ4-3-oxosteroids, a unique reaction that introduces a 90° bend at the A/B ring fusion to yield 5β-dihydrosteroids. AKR1D1 is the only enzyme capable of steroid 5β-reduction in humans and plays critical physiological roles. In steroid hormone metabolism, AKR1D1 serves mainly to inactivate the major classes of steroid hormones. AKR1D1 also catalyses key steps of the biosynthetic pathway of bile acids, which regulate lipid emulsification and cholesterol homoeostasis. Interestingly, AKR1D1 displayed a 20-fold variation in the kcat values, with steroid hormone substrates (e.g. aldosterone, testosterone and cortisone) having significantly higher kcat values than steroids with longer side chains (e.g. 7α-hydroxycholestenone, a bile acid precursor). Transient kinetic analysis revealed striking variations up to two orders of magnitude in the rate of the chemistry step (kchem), which resulted in different rate determining steps for the fast and slow substrates. By contrast, similar Kd values were observed for representative fast and slow substrates, suggesting similar rates of release for different steroid products. The release of NADP+ was shown to control the overall turnover for fast substrates, but not for slow substrates. Despite having high kchem values with steroid hormones, the kinetic control of AKR1D1 is consistent with the enzyme catalysing the slowest step in the catabolic sequence of steroid hormone transformation in the liver. The inherent slowness of the conversion of the bile acid precursor by AKR1D1 is also indicative of a regulatory role in bile acid synthesis.

  18. Bile acid interactions with cholangiocytes.

    PubMed

    Xia, Xuefeng; Francis, Heather; Glaser, Shannon; Alpini, Gianfranco; LeSage, Gene

    2006-06-14

    Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane. A selective transporter for bile acids, the Apical Sodium Bile Acid Cotransporter (ASBT) (also referred to as Ibat; gene name Slc10a2) is localized on the cholangiocyte apical membrane. On the basolateral membrane, four transport systems have been identified (t-ASBT, multidrug resistance (MDR)3, an unidentified anion exchanger system and organic solute transporter (Ost) heteromeric transporter, Ostalpha-Ostbeta. Together, these transporters unidirectionally move bile acids from ductal bile to the circulation. Bile acids absorbed by cholangiocytes recycle via the peribiliary plexus back to hepatocytes for re-secretion into bile. This recycling of bile acids between hepatocytes and cholangiocytes is referred to as the cholehepatic shunt pathway. Recent studies suggest that the cholehepatic shunt pathway may contribute in overall hepatobiliary transport of bile acids and to the adaptation to chronic cholestasis due to extrahepatic obstruction. ASBT is acutely regulated by an adenosine 3', 5'-monophosphate (cAMP)-dependent translocation to the apical membrane and by phosphorylation-dependent ubiquitination and proteasome degradation. ASBT is chronically regulated by changes in gene expression in response to biliary bile acid concentration and inflammatory cytokines. Another potential function of cholangiocyte ASBT is to allow cholangiocytes to sample biliary bile acids in order to activate intracellular signaling pathways. Bile acids trigger changes in intracellular calcium, protein kinase C (PKC), phosphoinositide 3-kinase (PI3K), mitogen-activated protein (MAP) kinase and extracellular signal-regulated protein kinase (ERK) intracellular signals. Bile acids significantly alter cholangiocyte secretion, proliferation and survival. Different bile acids have differential effects on cholangiocyte intracellular signals, and in some instances trigger opposing effects on cholangiocyte

  19. Bile acid interactions with cholangiocytes

    PubMed Central

    Xia, Xuefeng; Francis, Heather; Glaser, Shannon; Alpini, Gianfranco; LeSage, Gene

    2006-01-01

    Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane. A selective transporter for bile acids, the Apical Sodium Bile Acid Cotransporter (ASBT) (also referred to as Ibat; gene name Slc10a2) is localized on the cholangiocyte apical membrane. On the basolateral membrane, four transport systems have been identified (t-ASBT, multidrug resistance (MDR)3, an unidentified anion exchanger system and organic solute transporter (Ost) heteromeric transporter, Ostα-Ostβ. Together, these transporters unidirectionally move bile acids from ductal bile to the circulation. Bile acids absorbed by cholangiocytes recycle via the peribiliary plexus back to hepatocytes for re-secretion into bile. This recycling of bile acids between hepatocytes and cholangiocytes is referred to as the cholehepatic shunt pathway. Recent studies suggest that the cholehepatic shunt pathway may contribute in overall hepatobiliary transport of bile acids and to the adaptation to chronic cholestasis due to extrahepatic obstruction. ASBT is acutely regulated by an adenosine 3', 5’-monophosphate (cAMP)-dependent translocation to the apical membrane and by phosphorylation-dependent ubiquitination and proteasome degradation. ASBT is chronically regulated by changes in gene expression in response to biliary bile acid concentration and inflammatory cytokines. Another potential function of cholangiocyte ASBT is to allow cholangiocytes to sample biliary bile acids in order to activate intracellular signaling pathways. Bile acids trigger changes in intracellular calcium, protein kinase C (PKC), phosphoinositide 3-kinase (PI3K), mitogen-activated protein (MAP) kinase and extracellular signal-regulated protein kinase (ERK) intracellular signals. Bile acids significantly alter cholangiocyte secretion, proliferation and survival. Different bile acids have differential effects on cholangiocyte intracellular signals, and in some instances trigger opposing effects on cholangiocyte

  20. Post-acquisition filtering of salt cluster artefacts for LC-MS based human metabolomic studies.

    PubMed

    McMillan, A; Renaud, J B; Gloor, G B; Reid, G; Sumarah, M W

    2016-01-01

    Liquid chromatography-high resolution mass spectrometry (LC-MS) has emerged as one of the most widely used platforms for untargeted metabolomics due to its unparalleled sensitivity and metabolite coverage. Despite its prevalence of use, the proportion of true metabolites identified in a given experiment compared to background contaminants and ionization-generated artefacts remains poorly understood. Salt clusters are well documented artefacts of electrospray ionization MS, recognized by their characteristically high mass defects (for this work simply generalized as the decimal numbers after the nominal mass). Exploiting this property, we developed a method to identify and remove salt clusters from LC-MS-based human metabolomics data using mass defect filtering. By comparing the complete set of endogenous metabolites in the human metabolome database to actual plasma, urine and stool samples, we demonstrate that up to 28.5 % of detected features are likely salt clusters. These clusters occur irrespective of ionization mode, column type, sweep gas and sample type, but can be easily removed post-acquisition using a set of R functions presented here. Our mass defect filter removes unwanted noise from LC-MS metabolomics datasets, while retaining true metabolites, and requires only a list of m/z and retention time values. Reducing the number of features prior to statistical analyses will result in more accurate multivariate modeling and differential feature selection, as well as decreased reporting of unknowns that often constitute the largest proportion of human metabolomics data. PMID:27606010

  1. Apparent selective bile acid malabsorption as a consequence of ileal exclusion: effects on bile acid, cholesterol, and lipoprotein metabolism.

    PubMed Central

    Akerlund, J E; Björkhem, I; Angelin, B; Liljeqvist, L; Einarsson, K

    1994-01-01

    A new model has been developed to characterise the effect of a standardised ileal exclusion on bile acid, cholesterol, and lipoprotein metabolism in humans. Twelve patients treated by colectomy and ileostomy for ulcerative colitis were studied on two occasions: firstly with a conventional ileostomy and then three months afterwards with an ileal pouch operation with an ileoanal anastomosis and a protective loop ileostomy, excluding on average 95 cm of the distal ileum. The ileostomy contents were collected during 96 hours and the excretion of bile acids and cholesterol was determined using gas chromatography-mass spectrometry. Fasting blood and duodenal bile samples were collected on two consecutive days. After the exclusion of the distal ileum, both cholic and chenodeoxycholic acid excretion in the ileostomy effluent increased four to five times without any change in cholesterol excretion. Serum concentrations of lathosterol (a marker of cholesterol biosynthesis) and 7 alpha-hydroxycholesterol (a marker for bile acid biosynthesis) were increased several fold. Plasma concentrations of total VLDL triglycerides were also increased whereas the concentrations of total and LDL cholesterol, and apolipoprotein B were decreased. There were no changes in biliary lipid composition or cholesterol saturation of bile. The results show that the exclusion of about 95 cm of distal ileum causes malabsorption of bile acids but apparently not of cholesterol. The bile acid malabsorption leads to increased synthesis of both bile acids and cholesterol in the liver. It is suggested that bile acids can regulate cholesterol synthesis by a mechanism independent of the effect of bile acids on cholesterol absorption. The enhanced demand for cholesterol also leads to a decrease in plasma LDL cholesterol and apolipoprotein B concentrations. The malabsorption of bile acids did not affect biliary lipid composition or cholesterol saturations of VLDL triglycerides. PMID:7926917

  2. Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium

    PubMed Central

    Ridlon, Jason M.; Hylemon, Phillip B.

    2012-01-01

    The human bile acid pool composition is composed of both primary bile acids (cholic acid and chenodeoxycholic acid) and secondary bile acids (deoxycholic acid and lithocholic acid). Secondary bile acids are formed by the 7α-dehydroxylation of primary bile acids carried out by intestinal anaerobic bacteria. We have previously described a multistep biochemical pathway in Clostridium scindens that is responsible for bile acid 7α-dehydroxylation. We have identified a large (12 kb) bile acid inducible (bai) operon in this bacterium that encodes eight genes involved in bile acid 7α-dehydroxylation. However, the function of the baiF gene product in this operon has not been elucidated. In the current study, we cloned and expressed the baiF gene in E. coli and discovered it has bile acid CoA transferase activity. In addition, we discovered a second bai operon encoding three genes. The baiK gene in this operon was expressed in E. coli and found to encode a second bile acid CoA transferase. Both bile acid CoA transferases were determined to be members of the type III family by amino acid sequence comparisons. Both bile acid CoA transferases had broad substrate specificity, except the baiK gene product, which failed to use lithocholyl-CoA as a CoA donor. Primary bile acids are ligated to CoA via an ATP-dependent mechanism during the initial steps of 7α-dehydroxylation. The bile acid CoA transferases conserve the thioester bond energy, saving the cell ATP molecules during bile acid 7α-dehydroxylation. ATP-dependent CoA ligation is likely quickly supplanted by ATP-independent CoA transfer. PMID:22021638

  3. Rapid Determination of Bile Acids in Bile from Various Mammals by Reversed-Phase Ultra-Fast Liquid Chromatography.

    PubMed

    Si, Gu Leng Ri; Yao, Peng; Shi, Luwen

    2015-08-01

    A valid and efficient reversed-phase ultra-fast liquid chromatography method was developed for the simultaneous determination of 13 bile acids in the bile of three mammal species, including rat, pig and human gallstone patients. Chromatographic separation was performed with a Shim-pack XR-ODS column, and the mobile phase consisted of acetonitrile and potassium phosphate buffer (pH 2.6) at a flow rate of 0.5 mL min(-1). The linear detection range of most bile acids ranged from 2 to 600 ng µL(-1) with a good correlation coefficient (>0.9995). The precision of each bile acid was <1.8% for intraday and <4.8% for interday. All bile acids were separated in 15 min with satisfactory resolution, and the total analysis time was 18 min, including equilibration. The method was successfully applied in rapid screening of bile samples from the three mammals. Significant metabolic frameworks of bile acids among various species were observed, whereas considerable quantitative variations in both inter- and intraspecies were also observed, especially for gallstone patients. Our results suggest that detecting the change of bile acid profiles could be applied for the diagnosis of gallstone disease. PMID:25520305

  4. Aberrant bile ducts, 'remnant surface bile ducts,' and peribiliary glands: descriptive anatomy, historical nomenclature, and surgical implications.

    PubMed

    El Gharbawy, Ramadan M; Skandalakis, Lee J; Heffron, Thomas G; Skandalakis, John E

    2011-05-01

    The term "aberrant bile ducts" has been used to designate three heterogeneous groups of biliary structures: (1) bile ducts degenerating or disappearing (unknown etiology, diverse locations); (2) curious biliary structures in the transverse fissure; and (3) aberrant right bile ducts draining directly into the common hepatic duct. We report our observations on these three groups. Twenty-nine fresh human livers of stillborns and adults were injected differentially with colored latex and dissected. Adult livers showed portal venous and hepatic arterial branches, and bile ducts not associated with parenchyma, subjacent to and firmly adherent with the liver capsule: elements of ramifications of normal sheaths were present on the liver's surface. These ramifications, having lost parenchyma associated with them, then sequentially lost their portal branches, bile ducts and arterial branches. This process affected the ramifications of the sheaths in the left triangular ligament, adjacent to the inferior vena cava, in the gallbladder bed and anywhere else on the liver's surface and resulted in the presence of bile ducts accompanied by portal venous and/or hepatic arterial branches and not associated with parenchyma for a period of time. This first group represented normal bile ducts that do not meet the criteria of aberration and could be appropriately designated "remnant surface bile ducts." Such changes were not found in the transverse fissures and review of the literature revealed that the curious biliary structures are the microscopic peribiliary glands. The third group met the criteria of aberration and the anatomy of a representative duct is described.

  5. Post Mortem DNA Degradation of Human Tissue Experimentally Mummified in Salt

    PubMed Central

    Shved, Natallia; Haas, Cordula; Papageorgopoulou, Christina; Akguel, Guelfirde; Paulsen, Katja; Bouwman, Abigail; Warinner, Christina; Rühli, Frank

    2014-01-01

    Mummified human tissues are of great interest in forensics and biomolecular archaeology. The aim of this study was to analyse post mortem DNA alterations in soft tissues in order to improve our knowledge of the patterns of DNA degradation that occur during salt mummification. In this study, the lower limb of a female human donor was amputated within 24 h post mortem and mummified using a process designed to simulate the salt dehydration phase of natural or artificial mummification. Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis. Patterns of genomic fragmentation, miscoding lesions, and overall DNA degradation in both nuclear and mitochondrial DNA was assessed by different methods: gel electrophoresis, multiplex comparative autosomal STR length amplification, cloning and sequence analysis, and PCR amplification of different fragment sizes using a damage sensitive recombinant polymerase. The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle. PMID:25337822

  6. Post mortem DNA degradation of human tissue experimentally mummified in salt.

    PubMed

    Shved, Natallia; Haas, Cordula; Papageorgopoulou, Christina; Akguel, Guelfirde; Paulsen, Katja; Bouwman, Abigail; Warinner, Christina; Rühli, Frank

    2014-01-01

    Mummified human tissues are of great interest in forensics and biomolecular archaeology. The aim of this study was to analyse post mortem DNA alterations in soft tissues in order to improve our knowledge of the patterns of DNA degradation that occur during salt mummification. In this study, the lower limb of a female human donor was amputated within 24 h post mortem and mummified using a process designed to simulate the salt dehydration phase of natural or artificial mummification. Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis. Patterns of genomic fragmentation, miscoding lesions, and overall DNA degradation in both nuclear and mitochondrial DNA was assessed by different methods: gel electrophoresis, multiplex comparative autosomal STR length amplification, cloning and sequence analysis, and PCR amplification of different fragment sizes using a damage sensitive recombinant polymerase. The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle.

  7. Alteration of bile acid metabolism in the rat induced by chronic ethanol consumption

    PubMed Central

    Xie, Guoxiang; Zhong, Wei; Li, Houkai; Li, Qiong; Qiu, Yunping; Zheng, Xiaojiao; Chen, Huiyuan; Zhao, Xueqing; Zhang, Shucha; Zhou, Zhanxiang; Zeisel, Steven H.; Jia, Wei

    2013-01-01

    Our understanding of the bile acid metabolism is limited by the fact that previous analyses have primarily focused on a selected few circulating bile acids; the bile acid profiles of the liver and gastrointestinal tract pools are rarely investigated. Here, we determined how chronic ethanol consumption altered the bile acids in multiple body compartments (liver, gastrointestinal tract, and serum) of rats. Rats were fed a modified Lieber-DeCarli liquid diet with 38% of calories as ethanol (the amount equivalent of 4–5 drinks in humans). While conjugated bile acids predominated in the liver (98.3%), duodenum (97.8%), and ileum (89.7%), unconjugated bile acids comprised the largest proportion of measured bile acids in serum (81.2%), the cecum (97.7%), and the rectum (97.5%). In particular, taurine-conjugated bile acids were significantly decreased in the liver and gastrointestinal tract of ethanol-treated rats, while unconjugated and glycine-conjugated species increased. Ethanol consumption caused increased expression of genes involved in bile acid biosynthesis, efflux transport, and reduced expression of genes regulating bile acid influx transport in the liver. These results provide an improved understanding of the systemic modulations of bile acid metabolism in mammals through the gut-liver axis.—Xie, G., Zhong, W., Li, H., Li, Q., Qiu, Y., Zheng, X., Chen, H., Zhao, X., Zhang, S., Zhou, Z., Zeisel, S. H., Jia, W. Alteration of bile acid metabolism in the rat induced by chronic ethanol consumption. PMID:23709616

  8. Indirect Human Impacts Reverse Centuries of Carbon Sequestration and Salt Marsh Accretion

    PubMed Central

    Coverdale, Tyler C.; Brisson, Caitlin P.; Young, Eric W.; Yin, Stephanie F.; Donnelly, Jeffrey P.; Bertness, Mark D.

    2014-01-01

    Direct and indirect human impacts on coastal ecosystems have increased over the last several centuries, leading to unprecedented degradation of coastal habitats and loss of ecological services. Here we document a two-century temporal disparity between salt marsh accretion and subsequent loss to indirect human impacts. Field surveys, manipulative experiments and GIS analyses reveal that crab burrowing weakens the marsh peat base and facilitates further burrowing, leading to bank calving, disruption of marsh accretion, and a loss of over two centuries of sequestered carbon from the marsh edge in only three decades. Analogous temporal disparities exist in other systems and are a largely unrecognized obstacle in attaining sustainable ecosystem services in an increasingly human impacted world. In light of the growing threat of indirect impacts worldwide and despite uncertainties in the fate of lost carbon, we suggest that estimates of carbon emissions based only on direct human impacts may significantly underestimate total anthropogenic carbon emissions. PMID:24675669

  9. Complicated bile duct stones

    PubMed Central

    Roy, Ashwin; Martin, Derrick

    2013-01-01

    Common bile duct stones (CBDSs) are solid deposits that can either form within the gallbladder or migrate to the common bile duct (CBD), or form de novo in the biliary tree. In the USA around 15% of the population have gallstones and of these, 3% present with symptoms annually. Because of this, there have been major advancements in the management of gallstones and related conditions. Management is based on the patient's risk profile; young and healthy patients are likely to be recommended for surgery and elderly patients with comorbidities are usually recommended for endoscopic procedures. Imaging of gallstones has advanced in the last 30 years with endoscopic retrograde cholangiopancreatography evolving from a diagnostic to a therapeutic procedure in removing CBDSs. We present a complicated case of a patient with a CBDS and periampullary diverticulum and discuss the techniques used to diagnose and remove the stone from the biliary system. PMID:23946532

  10. Hormesis in Cholestatic Liver Disease; Preconditioning with Low Bile Acid Concentrations Protects against Bile Acid-Induced Toxicity

    PubMed Central

    Verhaag, Esther M.; Buist-Homan, Manon; Koehorst, Martijn; Groen, Albert K.; Moshage, Han; Faber, Klaas Nico

    2016-01-01

    Introduction Cholestasis is characterized by accumulation of bile acids and inflammation, causing hepatocellular damage. Still, liver damage markers are highest in acute cholestasis and drop when this condition becomes chronic, indicating that hepatocytes adapt towards the hostile environment. This may be explained by a hormetic response in hepatocytes that limits cell death during cholestasis. Aim To investigate the mechanisms that underlie the hormetic response that protect hepatocytes against experimental cholestatic conditions. Methods HepG2.rNtcp cells were preconditioned (24 h) with sub-apoptotic concentrations (0.1–50 μM) of various bile acids, the superoxide donor menadione, TNF-α or the Farsenoid X Receptor agonist GW4064, followed by a challenge with the apoptosis-inducing bile acid glycochenodeoxycholic acid (GCDCA; 200 μM for 4 h), menadione (50 μM, 6 h) or cytokine mixture (CM; 6 h). Levels of apoptotic and necrotic cell death, mRNA expression of the bile salt export pump (ABCB11) and bile acid sensors, as well as intracellular GCDCA levels were analyzed. Results Preconditioning with the pro-apoptotic bile acids GCDCA, taurocholic acid, or the protective bile acids (tauro)ursodeoxycholic acid reduced GCDCA-induced caspase-3/7 activity in HepG2.rNtcp cells. Bile acid preconditioning did not induce significant levels of necrosis in GCDCA-challenged HepG2.rNtcp cells. In contrast, preconditioning with cholic acid, menadione or TNF-α potentiated GCDCA-induced apoptosis. GCDCA preconditioning specifically reduced GCDCA-induced cell death and not CM- or menadione-induced apoptosis. The hormetic effect of GCDCA preconditioning was concentration- and time-dependent. GCDCA-, CDCA- and GW4064- preconditioning enhanced ABCB11 mRNA levels, but in contrast to the bile acids, GW4064 did not significantly reduce GCDCA-induced caspase-3/7 activity. The GCDCA challenge strongly increased intracellular levels of this bile acid, which was not lowered by GCDCA

  11. Bile acids: emerging role in management of liver diseases

    PubMed Central

    Asgharpour, Amon; Kumar, Divya

    2016-01-01

    Bile acids are well known for their effects on cholesterol homeostasis and lipid digestion. Since the discovery of bile acid receptors, of which there are farnesoid X receptor (FXR), a nuclear receptor, and the plasma membrane G-protein receptor, as well as Takeda G-protein coupled receptor clone 5, further roles have been elucidated for bile acids including glucose and lipid metabolism as well as inflammation. Additionally, treatment with bile acid receptor agonists has shown a decrease in the amount of atherosclerosis plaque formation and decreased portal vascular resistance and portal hypotension in animal models. Furthermore, rodent models have demonstrated antifibrotic activity using bile acid receptor agonists. Early human data using a FXR agonist, obeticholic acid, have shown promising results with improvement of histological activity and even a reduction of fibrosis. Human studies are ongoing and will provide further information on bile acid receptor agonist therapies. Thus, bile acids and their derivatives have the potential for management of liver diseases and potentially other disease states including diabetes and the metabolic syndrome. PMID:26320013

  12. Therapeutic targeting of bile acids

    PubMed Central

    Gores, Gregory J.

    2015-01-01

    The first objectives of this article are to review the structure, chemistry, and physiology of bile acids and the types of bile acid malabsorption observed in clinical practice. The second major theme addresses the classical or known properties of bile acids, such as the role of bile acid sequestration in the treatment of hyperlipidemia; the use of ursodeoxycholic acid in therapeutics, from traditional oriental medicine to being, until recently, the drug of choice in cholestatic liver diseases; and the potential for normalizing diverse bowel dysfunctions in irritable bowel syndrome, either by sequestering intraluminal bile acids for diarrhea or by delivering more bile acids to the colon to relieve constipation. The final objective addresses novel concepts and therapeutic opportunities such as the interaction of bile acids and the microbiome to control colonic infections, as in Clostridium difficile-associated colitis, and bile acid targeting of the farnesoid X receptor and G protein-coupled bile acid receptor 1 with consequent effects on energy expenditure, fat metabolism, and glycemic control. PMID:26138466

  13. Dissection of the hierarchy and synergism of the bile derived signal on Cryptosporidium parvum excystation and infectivity.

    PubMed

    King, B J; Keegan, A R; Phillips, R; Fanok, S; Monis, P T

    2012-10-01

    Bile salts have been identified as an important trigger for excystation of Cryptosporidium oocysts but the hierarchy or synergism of this signal in relation to other triggers involved in excystation is poorly understood. In addition to excystation, bile salts have also been reported to increase the invasiveness of sporozoites within in vitro culture, possibly by affecting the secretory pathway via modification of intracellular calcium signalling. Nevertheless, incorporation of bile or bile salts into in vitro assays is not universal, with recent reports of negative effects on parasite growth. Here we report that bile and sodium taurocholate significantly affect both excystation rate and parasite in vitro growth. We demonstrate that their effect on excystation is dose, time and pre-treatment temperature dependent, while increases in parasite replication appear to be associated with modulation of parasite intracellular calcium and increased host cell susceptibility to infection. Notably, we illustrate that bile has a significant effect on host cells and can be cytotoxic at concentrations not much higher than those currently used for in vitro assays. This work should assist with more rational design of in vitro culture systems, with significant considerations for assay format when incorporating bile or bile salts as an excystation trigger. PMID:22894830

  14. Variants in Striatin Gene are Associated with Salt Sensitive Blood Pressure in Mice and Humans

    PubMed Central

    Sun, Bei; Williams, Jonathan; Lasky-Su, Jessica; Baudrand, Rene; Yao, Tham; Moize, Burhanuddin; Hafiz, Wan M; Romero, Jose R.; Adler, Gail K.; Ferri, Claudio; Hopkins, Paul N.; Pojoga, Luminita H.; Williams, Gordon H.

    2015-01-01

    Striatin is a novel protein that interacts with steroid receptors and modifies rapid, non-genomic activity in vitro. We tested the hypothesis that striatin would in turn affect mineralocorticoid receptor function and consequently sodium, water, and blood pressure homeostasis in an animal model. We evaluated salt sensitivity of blood pressure in novel striatin heterozygote knockout mice. When compared with wild type, striatin heterozygote exhibited a significant increase in blood pressure when sodium intake was increased from restricted (0.03%) to liberal (1.6%) sodium). Further, renal expression of mineralocorticoid receptor and its genomic downstream targets serum/glucocoticoid-regulated kinase 1 and epithelial sodium channel were increased in striatin heterozygote versus wild type mice on liberal sodium intake while the pAkt/Akt ratio, readout of mineralocoriticoid receptor's rapid, non-genomic pathway, was reduced. To determine the potential clinical relevance of these findings, we tested the association between single nucleotide polymorphic variants of striatin gene and salt sensitivity of blood presure in 366 Caucasian hypertensive subjects. HapMap derived tagging single nucleotide polymorphisms identified an association between rs2540923 with salt sensitivity of blood pressure (OR, 6.25; 95% CI 1.7-20; P=0.01). These data provide the first in vivo evidence in humans and rodents that associates striatin with markers of mineralocoriticoid receptor activity. The data also support the hypothesis that the rapid, non-genomic mineralocoriticoid receptor pathway (mediated via striatin) has a role in modulating the interaction between salt intake and blood pressure. PMID:25368024

  15. Characterization of Salt-Induced Oligomerization of Human β2-Microglobulin at Low pH.

    PubMed

    Narang, Dominic; Singh, Anubhuti; Swasthi, Hema M; Mukhopadhyay, Samrat

    2016-08-18

    Misfolding and amyloid aggregation of human β2-microglobulin (β2m) have been linked to dialysis-related amyloidosis. Previous studies have shown that in the presence of different salt concentrations and at pH 2.5, β2m assembles into aggregates with distinct morphologies. However, the structural and mechanistic details of the aggregation of β2m, giving rise to different morphologies, are poorly understood. In this work, we have extensively characterized the salt-induced oligomers of the acid-unfolded state of β2m using an array of biophysical tools including steady-state and time-resolved fluorescence, circular dichroism, dynamic light scattering, and atomic force microscopy imaging. Fluorescence studies using the oligomer-sensitive molecular rotor, 4-(dicyanovinyl)-julolidine, in conjunction with the light scattering and cross-linking assay indicated that at low salt (NaCl) concentrations β2m exists as a disordered monomer, capable of transforming into ordered amyloid. In the presence of higher concentrations of salt, β2m aggregates into a larger oligomeric species that does not appear to transform into amyloid fibrils. Site-specific fluorescence experiments using single Trp variants of β2m revealed that the middle region of the protein is incorporated into these oligomers, whereas the C-terminal segment is highly exposed to bulk water. Additionally, stopped-flow kinetic experiments indicated that the formation of hydrophobic core and oligomerization occur concomitantly. Our results revealed the distinct pathways by which β2m assembles into oligomers and fibrils. PMID:27467899

  16. Evaluation of calcium magnesium acetate and road salt for contact hypersensitivity potential and dermal irritancy in humans.

    PubMed

    Cushman, J R; Duff, V A; Buteau, G H; Aust, L B; Caldwell, N; Lazer, W

    1991-04-01

    Calcium magnesium acetate (CMA) and road salt are both de-icing agents to which workers may be dermally exposed. A commercial formulation of CMA (Chevron Ice-B-Gon Deicer) and road salt were tested in a human repeat insult patch test to evaluate the contact hypersensitivity potential of these materials and to evaluate irritation following single or multiple applications. 72 of the initial 82 panelists completed the study. CMA and road salt (each at 10% and 30% w/w in distilled water; 0.3 ml) were administered under occlusive patches on the forearm for 14 h 3 x per week for 3 weeks. The panelists were challenged 2 weeks later; 2 panelists who had mild reactions were subsequently rechallenged 6 weeks later. Neither CMA nor road salt produced contact hypersensitivity in any panelists. Following the first application, moderate acute irritation was observed only at 1 skin site exposed to 30% road salt. Repeated exposure to CMA or road salt produced mild to moderate irritation. The highest incidence of moderate irritation was observed with 30% road salt. Thus, neither material is expected to cause significant dermal effects in exposed workers. CMA is expected to cause dermal irritation equivalent to or less than that caused by road salt.

  17. Laser spectroscopy and imaging of gallbladder stones, tissue and bile

    NASA Astrophysics Data System (ADS)

    Marafi, M.; Kokaj, J.; Bhatia, K. S.; Makdisi, Y.; Mathew, K.

    2007-01-01

    Laser spectroscopic study of billary calculi and tissues is described. Fluorescence spectra of human gallbladder stones, bile and tissues were recorded with streak camera in the frequency and time domain. Potential of fluorescence as a diagnostic tool to discriminate between the intended target and the surrounding tissues and bile is evaluated. Initiation of fragmentation process is visualized by high-speed shadowgraphy, interferometry performed during the laser impact and generation of plasma causing growth and collapse of bubbles.

  18. Steam Cooking Significantly Improves in Vitro Bile Acid Binding of Beets, Eggplant, Asparagus, Carrots, Green Beans and Cauliflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The relative healthful potential of cooked beets, okra, eggplant, asparagus, carrots, green beans, cauliflower and turnips was evaluated by determining their in vitro bile acid binding using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two...

  19. SK&F 97426-A: a novel bile acid sequestrant with higher affinities and slower dissociation rates for bile acids in vitro than cholestyramine.

    PubMed

    Benson, G M; Alston, D R; Hickey, D M; Jaxa-Chamiec, A A; Whittaker, C M; Haynes, C; Glen, A; Blanchard, S; Cresswell, S R; Suckling, K E

    1997-01-01

    SK&F 97426-A is a novel bile acid sequestrant that is threefold more potent than cholestyramine at increasing bile acid excretion in the hamster. SK&F 97426-A is a quaternary alkylammonium polymethacrylate that was selected for comparison with cholestyramine in vivo because of its superior in vitro bile acid binding properties. Association, dissociation, affinity, and capacity experiments were performed under physiologically relevant conditions with the most abundant bile acids found in human bile. The bile acids came to equilibrium with SK&F 97426-A and cholestyramine within approximately 30 min and 6 min, respectively. SK&F 97426-A and cholestyramine had similar capacities for all the bile acids (between 2.5 and 4 mmol/g) and both had similar, very high affinities and slow dissociation rates for the dihydroxy bile acids. However, SK&F 97426-A had much higher affinities for the trihydroxy bile acids glycocholic acid and taurocholic acid than did cholestyramine. Dissociation of glycocholic acid and taurocholic acid from SK&F 97426-A was also much slower (27 and 25%, respectively, dissociated after 60 min) than from cholestyramine (89 and 84%, respectively, dissociated after 60 min). The higher affinities and slower dissociation rates of the trihydroxy bile acids for and from SK&F 97426-A probably account for the increased potency of SK&F 97426-A over cholestyramine in vivo.

  20. Less hydrophobic phosphatidylcholine species simplify biliary vesicle morphology, but induce bile metastability with a broad spectrum of crystal forms.

    PubMed Central

    Sakomoto, Minoru; Tazuma, Susumu; Chayama, Kazuaki

    2002-01-01

    Cholesterol crystallization in bile is affected by phosphatidylcholine (PtdCho) hydrophobicity. The aim of the present study was to determine whether PtdCho species modulate the metastable-labile limit and equilibrium solubility of cholesterol in the micellar phase of bile, thereby altering the distribution of cholesterol to biliary lipid carriers and thus influencing cholesterol crystallization. Supersaturated model bile (with a cholesterol saturation index of 2.0 and a total lipid concentration of 10 g/dl) was prepared with various PtdCho/(bile salt+PtdCho) ratios (0.1-0.5) using egg yolk or soya bean PtdCho. Subsequently, the following features were determined: metastable-labile limit, equilibrium solubility of cholesterol, metastable zone, and cholesterol crystallization process. Less hydrophobic PtdCho species destabilized bile cholesterol to induce rapid crystallization, because of a broad integrated metastable zone, whereas more hydrophobic species stabilized bile cholesterol with a less integrated metastable zone and thus retarded cholesterol crystallization. Cholesterol crystallization was accelerated by a decrease in the PtdCho/(bile salt+PtdCho) ratio, whereas the final nucleated crystal mass was increased by an increase in this ratio. With decreasing hydrophobicity of the PtdCho species, the intermixed micellar/vesicular concentration of bile salts decreased in association with less formation of vesicles and increased formation of micelles, and a variety of crystal forms were detected. In conclusion, PtdCho species directly influenced the cholesterol crystallization process in model bile by remodelling the bile mesophase, and also had an indirect influence by altering the balance between bile salt micelles and vesicles. PMID:11829745

  1. Less hydrophobic phosphatidylcholine species simplify biliary vesicle morphology, but induce bile metastability with a broad spectrum of crystal forms.

    PubMed

    Sakomoto, Minoru; Tazuma, Susumu; Chayama, Kazuaki

    2002-02-15

    Cholesterol crystallization in bile is affected by phosphatidylcholine (PtdCho) hydrophobicity. The aim of the present study was to determine whether PtdCho species modulate the metastable-labile limit and equilibrium solubility of cholesterol in the micellar phase of bile, thereby altering the distribution of cholesterol to biliary lipid carriers and thus influencing cholesterol crystallization. Supersaturated model bile (with a cholesterol saturation index of 2.0 and a total lipid concentration of 10 g/dl) was prepared with various PtdCho/(bile salt+PtdCho) ratios (0.1-0.5) using egg yolk or soya bean PtdCho. Subsequently, the following features were determined: metastable-labile limit, equilibrium solubility of cholesterol, metastable zone, and cholesterol crystallization process. Less hydrophobic PtdCho species destabilized bile cholesterol to induce rapid crystallization, because of a broad integrated metastable zone, whereas more hydrophobic species stabilized bile cholesterol with a less integrated metastable zone and thus retarded cholesterol crystallization. Cholesterol crystallization was accelerated by a decrease in the PtdCho/(bile salt+PtdCho) ratio, whereas the final nucleated crystal mass was increased by an increase in this ratio. With decreasing hydrophobicity of the PtdCho species, the intermixed micellar/vesicular concentration of bile salts decreased in association with less formation of vesicles and increased formation of micelles, and a variety of crystal forms were detected. In conclusion, PtdCho species directly influenced the cholesterol crystallization process in model bile by remodelling the bile mesophase, and also had an indirect influence by altering the balance between bile salt micelles and vesicles.

  2. Intrahepatic Transposition of Bile Ducts

    PubMed Central

    Delić, Jasmin; Savković, Admedina; Isaković, Eldar; Marković, Sergije; Bajtarevic, Alma; Denjalić, Amir

    2012-01-01

    Objective. To describe the intrahepatic bile duct transposition (anatomical variation occurring in intrahepatic ducts) and to determine the frequency of this variation. Material and Methods. The researches were performed randomly on 100 livers of adults, both sexes. Main research methods were anatomical macrodissection. As a criterion for determination of variations in some parts of bile tree, we used the classification of Segmentatio hepatis according to Couinaud (1957) according to Terminologia Anatomica, Thieme Stuugart: Federative Committee on Anatomical Terminology, 1988. Results. Intrahepatic transposition of bile ducts was found in two cases (2%), out of total examined cases (100): right-left transposition (right segmental bile duct, originating from the segment VIII, joins the left liver duct-ductus hepaticus sinister) and left-right intrahepatic transposition (left segmental bile duct originating from the segment IV ends in right liver duct-ductus hepaticus dexter). Conclusion. Safety and success in liver transplantation to great extent depends on knowledge of anatomy and some common embryological anomalies in bile tree. Variations in bile tree were found in 24–43% of cases, out of which 1–22% are the variations of intrahepatic bile ducts. Therefore, good knowledge on ductal anatomy enables good planning, safe performance of therapeutic and operative procedures, and decreases the risk of intraoperative and postoperative complications. PMID:22550601

  3. Elevation of Fasting Ghrelin in Healthy Human Subjects Consuming a High-Salt Diet: A Novel Mechanism of Obesity?

    PubMed Central

    Zhang, Yong; Li, Fenxia; Liu, Fu-Qiang; Chu, Chao; Wang, Yang; Wang, Dan; Guo, Tong-Shuai; Wang, Jun-Kui; Guan, Gong-Chang; Ren, Ke-Yu; Mu, Jian-Jun

    2016-01-01

    Overweight/obesity is a chronic disease that carries an increased risk of hypertension, diabetes mellitus, and premature death. Several epidemiological studies have demonstrated a clear relationship between salt intake and obesity, but the pathophysiologic mechanisms remain unknown. We hypothesized that ghrelin, which regulates appetite, food intake, and fat deposition, becomes elevated when one consumes a high-salt diet, contributing to the progression of obesity. We, therefore, investigated fasting ghrelin concentrations during a high-salt diet. Thirty-eight non-obese and normotensive subjects (aged 25 to 50 years) were selected from a rural community in Northern China. They were sequentially maintained on a normal diet for three days at baseline, a low-salt diet for seven days (3 g/day, NaCl), then a high-salt diet for seven days (18 g/day). The concentration of plasma ghrelin was measured using an immunoenzyme method (ELISA). High-salt intake significantly increased fasting ghrelin levels, which were higher during the high-salt diet (320.7 ± 30.6 pg/mL) than during the low-salt diet (172.9 ± 8.9 pg/mL). The comparison of ghrelin levels between the different salt diets was statistically-significantly different (p < 0.01). A positive correlation between 24-h urinary sodium excretion and fasting ghrelin levels was demonstrated. Our data indicate that a high-salt diet elevates fasting ghrelin in healthy human subjects, which may be a novel underlying mechanism of obesity. PMID:27240398

  4. Maternal bile acid transporter deficiency promotes neonatal demise

    PubMed Central

    Zhang, Yuanyuan; Li, Fei; Wang, Yao; Pitre, Aaron; Fang, Zhong-ze; Frank, Matthew W.; Calabrese, Christopher; Krausz, Kristopher W.; Neale, Geoffrey; Frase, Sharon; Vogel, Peter; Rock, Charles O.; Gonzalez, Frank J.; Schuetz, John D.

    2015-01-01

    Intrahepatic cholestasis of pregnancy (ICP) is associated with adverse neonatal survival and is estimated to impact between 0.4 and 5% of pregnancies worldwide. Here we show that maternal cholestasis (due to Abcb11 deficiency) produces neonatal death among all offspring within 24 h of birth due to atelectasis-producing pulmonary hypoxia, which recapitulates the neonatal respiratory distress of human ICP. Neonates of Abcb11-deficient mothers have elevated pulmonary bile acids and altered pulmonary surfactant structure. Maternal absence of Nr1i2 superimposed on Abcb11 deficiency strongly reduces maternal serum bile acid concentrations and increases neonatal survival. We identify pulmonary bile acids as a key factor in the disruption of the structure of pulmonary surfactant in neonates of ICP. These findings have important implications for neonatal respiratory failure, especially when maternal bile acids are elevated during pregnancy, and highlight potential pathways and targets amenable to therapeutic intervention to ameliorate this condition. PMID:26416771

  5. Maternal bile acid transporter deficiency promotes neonatal demise.

    PubMed

    Zhang, Yuanyuan; Li, Fei; Wang, Yao; Pitre, Aaron; Fang, Zhong-Ze; Frank, Matthew W; Calabrese, Christopher; Krausz, Kristopher W; Neale, Geoffrey; Frase, Sharon; Vogel, Peter; Rock, Charles O; Gonzalez, Frank J; Schuetz, John D

    2015-09-29

    Intrahepatic cholestasis of pregnancy (ICP) is associated with adverse neonatal survival and is estimated to impact between 0.4 and 5% of pregnancies worldwide. Here we show that maternal cholestasis (due to Abcb11 deficiency) produces neonatal death among all offspring within 24 h of birth due to atelectasis-producing pulmonary hypoxia, which recapitulates the neonatal respiratory distress of human ICP. Neonates of Abcb11-deficient mothers have elevated pulmonary bile acids and altered pulmonary surfactant structure. Maternal absence of Nr1i2 superimposed on Abcb11 deficiency strongly reduces maternal serum bile acid concentrations and increases neonatal survival. We identify pulmonary bile acids as a key factor in the disruption of the structure of pulmonary surfactant in neonates of ICP. These findings have important implications for neonatal respiratory failure, especially when maternal bile acids are elevated during pregnancy, and highlight potential pathways and targets amenable to therapeutic intervention to ameliorate this condition.

  6. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  7. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  8. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  9. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  10. 21 CFR 100.155 - Salt and iodized salt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Salt and iodized salt. 100.155 Section 100.155... FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized salt. (a) For the purposes of this section, the term iodized salt or iodized table salt is...

  11. Acute angiotensin II increases plasma F2-isoprostanes in salt-replete human hypertensives.

    PubMed

    Murphey, Laine J; Morrow, Jason D; Sawathiparnich, Pairunyar; Williams, Gordon H; Vaughan, Douglas E; Brown, Nancy J

    2003-10-01

    Angiotensin (Ang) II induces oxidative stress in vitro and in animal models of hypertension. We tested the hypothesis that Ang II increases oxidative stress in human hypertension, as assessed by plasma F2-isoprostane concentrations. Plasma F2-isoprostanes, hemodynamic and endocrine parameters were measured at baseline and following a 55 min infusion of 3 ng/kg/min Ang II in 13 normotensive and 13 hypertensive volunteers ingesting a high- (200 mmol/d) or low- (10 mmol/d) sodium diet. Mean arterial pressure (MAP) and body mass index were higher in hypertensive subjects. Ang II infusion increased MAP (p<.001) and plasma aldosterone concentrations (p<.001) and decreased plasma renin activity (p<.001) and renal plasma flow (p<.001) to a similar extent in both groups. Plasma F2-isoprostane concentrations were similar at baseline. There was no effect of Ang II on F2-isoprostane concentrations during low-salt intake in either group (normotensive 51.7 +/- 7.1 to 53.7 +/- 6.5 pg/ml and hypertensive 52.2 +/- 8.2 to 56.2 +/- 10.0 pg/ml; mean +/- SE). During high-salt intake, Ang II increased F2-isoprostane concentrations in the hypertensive group (52.3 +/- 7.2 to 63.2 +/- 10.4 pg/ml, p=0.010) but not in the normotensive group (54.2 +/- 4.4 to 58.9 +/- 6.6 pg/ml, p=0.83). Acute Ang II infusion increases oxidative stress in vivo in hypertensive humans. The renin-angiotensin system may contribute to oxidative stress in human cardiovascular disease.

  12. Monitoring of glucose, salt and pure water in human whole blood: An in vitro study.

    PubMed

    Imran, Muhammad; Ullah, Hafeez; Akhtar, Munir; Sial, Muhammad Aslam; Ahmed, Ejaz; Durr-E-Sabeeh; Ahmad, Mukhtar; Hussain, Fayyaz

    2016-07-01

    Designing and implementation of non-invasive methods for glucose monitoring in blood is main focus of biomedical scientists to provide a relief from skin puncturing of diabete patient. The objective of this research work is to investigate the shape deformations and the aggregation of red blood cells (RBCs) in the human blood after addition of three different analytes i) (0mM-400mM: Range) of glucose (C(6)H(12)O(6)), ii) (0mM-400mM: range) of pure salt (NaCl) and iii) (0mM- 350mM: range) of pure water (H(2)O). We have observed that the changes in the shape of individual cells from biconcave discs to spherical shapes and eventually the lysis of the cells at optimum concentration of glucose, salts and pure water. This demonstration also provides a base line to facilitate diabetes during partial diagnosis and monitoring of the glucose levels qualitatively both in research laboratories and clinical environment. PMID:27393437

  13. Hydrophobic interactions are involved in the inhibition of human leukocyte elastase by alkyltrimethylammonium salts.

    PubMed

    Kouadri-Boudjelthia, A; Wallach, J M

    1997-02-01

    Electrostatic forces and hydrophobic interactions had been suggested to modify the adsorption of elastases onto insoluble fibrous elastin, which is the initial stage of elastolysis, but conflicting results had been obtained, and comparison between compounds with different structures was difficult. In order to explore these observations, we have studied the effect of six alkyltrimethylammonium bromides, with alkyl chain length ranging from six to 16 carbon atoms, on human leucocyte elastase activities, either with a synthetic substrate or with insoluble elastin. The enzymatic studies were performed either spectrophotometrically or using conductimetry, and direct binding on to elastin was conductimetrically measured. Binding of the alkyltrimethylammonium salts is increasing with alkyl chain length and we could demonstrate a cooperative binding for tetra- and hexadecyl chains. No effect of the six compounds could be evidenced on hydrolysis of a specific synthetic substrate. With insoluble elastin, elastolysis inhibition could be demonstrated for alkyl chain longer than ten carbon atoms, the effect increasing with chain length. A similar inhibition was observed with the soluble kappa-elastin, but it was less effective. The study shows that the interaction between the alkyltrimethylammonium salts and elastin plays a major role in the inhibitory potency of these molecules. As this effect is enhanced with alkyl chain length, it was concluded that hydrophobic interactions favour their binding, protecting elastin against elastase adsorption.

  14. More relevant prediction for in vivo drug interaction of candesartan cilexetil on hepatic bile acid transporter BSEP using sandwich-cultured hepatocytes.

    PubMed

    Fukuda, Hajime; Nakanishi, Takeo; Tamai, Ikumi

    2014-01-01

      Bile salt export pump (BSEP) plays a major role in biliary secretion of bile salts; therefore, drug-induced cholestasis could occur because of BSEP inhibition by drugs. Drug interaction on hepatic bile canalicular transporters such as BSEP with prodrugs that are rapidly metabolized has not been evaluated well. In the present study, candesartan cilexetil (CIL) was used as a model compound and its inhibitory potential against BSEP was determined in sandwich-cultured human hepatocytes (hSCH) as well as in BSEP-expressing membrane vesicles. CIL exhibited potent BSEP inhibition with an IC50 value of 6.2 µM in the transport assay using membrane vesicles. In contrast, BSEP inhibition by CIL was not observed in hSCH after 120 min exposure. This discordance is possibly explained by metabolic elimination of CIL in hSCH because BSEP inhibition became reversely pronounced under the conditions where CIL metabolism was suppressed by diisopropyl fluorophosphates. The results observed in hSCH are consistent with the fact that liver dysfunction or jaundice occurs with low frequency in clinical use of CIL, which may not be obtained by membrane vesicle study on the effect of CIL on BSEP.

  15. Ligand-dependent coactivation of the human bile acid receptor FXR by the peroxisome proliferator-activated receptor gamma coactivator-1alpha.

    PubMed

    Savkur, Rajesh S; Thomas, Jeffrey S; Bramlett, Kelli S; Gao, Yunling; Michael, Laura F; Burris, Thomas P

    2005-01-01

    Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) has been shown to play an important role in energy metabolism by coordinating transcriptional programs involved in mitochondrial biogenesis, adaptive thermogenesis, gluconeogenesis, and fatty acid oxidation. PGC-1alpha also plays a crucial role in cholesterol metabolism by serving as a coactivator of the liver X receptor-alpha and inducing the expression of cholesterol 7-alpha-hydroxylase. Here, we demonstrate that PGC-1alpha also functions as an effective coactivator of farnesoid X receptor (FXR), the bile acid receptor. Transient cotransfection assays demonstrate that PGC-1alpha enhances ligand-mediated FXR transcription when either full-length FXR or Gal4 DNA binding domain-FXR-ligand binding domain chimeras were analyzed. Mammalian two-hybrid analyses, glutathione S-transferase affinity chromatography and biochemical coactivator recruitment assays demonstrate ligand-dependent interaction between the two proteins both in vivo and in vitro. PGC-1alpha-mediated coactivation of FXR was highly ligand-dependent and absolutely required an intact activation function-2 (AF-2) domain of FXR and the LXXLL motif in PGC-1alpha. The integrity of the charge clamp was required, further illustrating the role of the ligand binding domain of FXR in PGC-1alpha recognition. Together, these results indicate that PGC-1alpha functions as a potent coactivator for FXR and further implicates its role in the regulation of genes that are involved in bile acid and lipid metabolism.

  16. Non-Newtonian flow of pathological bile in the biliary system: experimental investigation and CFD simulations

    NASA Astrophysics Data System (ADS)

    Kuchumov, Alex G.; Gilev, Valeriy; Popov, Vitaliy; Samartsev, Vladimir; Gavrilov, Vasiliy

    2014-02-01

    The paper presents an experimental study of pathological human bile taken from the gallbladder and bile ducts. The flow dependences were obtained for different types of bile from patients with the same pathology, but of different age and sex. The parameters of the Casson's and Carreau's equations were found for bile samples. Results on the hysteretic bile behavior at loading-unloading tests are also presented, which proved that the pathologic bile is a non-Newtonian thixotropic liquid. The viscosity of the gallbladder bile was shown to be higher compared to the duct bile. It was found that at higher shear stress the pathological bile behaves like Newtonian fluid, which is explained by reorientation of structural components. Moreover, some pathological bile flow in the biliary system CFD simulations were performed. The velocity and pressure distributions as well as flow rates in the biliary segments during the gallbladder refilling and emptying phases are obtained. The results of CFD simulations can be used for surgeons to assess the patient's condition and choose an adequate treatment.

  17. Protective effects of nonionic tri-block copolymers on bile acid-mediated epithelial barrier disruption.

    SciTech Connect

    Edelstein, A.; Fink, D.; Musch, M.; Valuckaite, V.; Zabornia, O.; Grubjesic, S.; Firestone, M. A.; Matthews, J. B.; Alverdy, J. C.

    2011-11-01

    Translocation of bacteria and other luminal factors from the intestine following surgical injury can be a major driver of critical illness. Bile acids have been shown to play a key role in the loss of intestinal epithelial barrier function during states of host stress. Experiments to study the ability of nonionic block copolymers to abrogate barrier failure in response to bile acid exposure are described. In vitro experiments were performed with the bile salt sodium deoxycholate on Caco-2 enterocyte monolayers using transepithelial electrical resistance to assay barrier function. A bisphenol A coupled triblock polyethylene glycol (PEG), PEG 15-20, was shown to prevent sodium deoxycholate-induced barrier failure. Enzyme-linked immunosorbent assay, lactate dehydrogenase, and caspase 3-based cell death detection assays demonstrated that bile acid-induced apoptosis and necrosis were prevented with PEG 15-20. Immunofluorescence microscopic visualization of the tight junctional protein zonula occludens 1 (ZO-1) demonstrated that PEG 15-20 prevented significant changes in tight junction organization induced by bile acid exposure. Preliminary transepithelial electrical resistance-based studies examining structure-function correlates of polymer protection against bile acid damage were performed with a small library of PEG-based copolymers. Polymer properties associated with optimal protection against bile acid-induced barrier disruption were PEG-based compounds with a molecular weight greater than 10 kd and amphiphilicity. The data demonstrate that PEG-based copolymer architecture is an important determinant that confers protection against bile acid injury of intestinal epithelia.

  18. The effects of tiadenol, clofibrate and clofibride on bile composition in the rat.

    PubMed

    Rozé, C; Cuchet, P; Souchard, M; Vaille, C; Debray, C

    1977-05-01

    Biliary secretion was studied in normolipidemic rats after a 7 day treatment with the hypolipidemic drugs, tiadenol (bis-(hydroxyethylthio)-1,10-decane), clofibrate and clofibride (chloro-4-phenoxy-2-methyl-2-propionate of dimethylcarbamoyl-3-propyl). All three drugs decreased blood cholesterol and total lipids, increased liver weight and liver catalase content, and decreased biliary excretion of cholesterol. The biliary concentrations of bile salts, phospholipids and cholesterol decreased to a variable extent, in such a way that the ratio of bile salts + phospholipids to cholesterol was increased by the drugs. The bile salt independent fraction was increased. The effects were qualitatively similar for all three drugs tested, but quanitative differences appeared for some of the parameters. PMID:862664

  19. CT evaluation of intracholecystic bile

    SciTech Connect

    Rebner, M.; Ruggieri, P.M.; Gross, B.H.; Glazer, G.M.

    1985-08-01

    Computed tomography (CT) has been used to detect a variety of gallbladder abnormalities, but the accuracy of routine abdominal CT in evaluating intracholecystic bile has not been established. Forty-six patients were identified in whom abdominal CT and sonography were performed within 1 week of each other. Using sonographic results as the standard, sensitivity specificity, and accuracy of CT gallbladder evaluation were calculated; both initial CT interpretations and retrospective review of scans were used for this analysis. In the retrospective review, visual interpretation of gallbladder images and measurement of intracholecystic bile attenuation were analyzed. The most common cause of high-attenuation bile in the series was sludge, a cause not previously reported. It was concluded that intracholecystic bile is poorly evaluated on routine abdominal CT, particularly because of low sensitivity in disease detection.

  20. A biosynthetic pathway for a prominent class of microbiota-derived bile acids

    PubMed Central

    Devlin, A. Sloan; Fischbach, Michael A.

    2015-01-01

    The gut bile acid pool is millimolar in concentration, varies widely in composition among individuals, and is linked to metabolic disease and cancer. Although these molecules derive almost exclusively from the microbiota, remarkably little is known about which bacterial species and genes are responsible for their biosynthesis. Here, we report a biosynthetic pathway for the second most abundant class in the gut, iso (3β-hydroxy) bile acids, whose levels exceed 300 µM in some humans and are absent in others. We show, for the first time, that iso bile acids are produced by Ruminococcus gnavus, a far more abundant commensal than previously known producers; and that the iso bile acid pathway detoxifies deoxycholic acid, favoring the growth of the keystone genus Bacteroides. By revealing the biosynthetic genes for an abundant class of bile acids, our work sets the stage for predicting and rationally altering the composition of the bile acid pool. PMID:26192599

  1. 21 CFR 184.1560 - Ox bile extract.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ox bile extract. 184.1560 Section 184.1560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... known as purified oxgall or sodium choleate, is a yellowish green, soft solid, with a partly...

  2. [Bile acids in coronary arteriosclerosis].

    PubMed

    Malaia, L T; Shelest, A N; Volkov, V I; Cherevatov, B G

    1984-10-01

    Seventy-six patients with chronic coronary heart disease of the atherosclerotic genesis were examined using clinical laboratory and instrumental research methods. The blood serum levels of total cholesterol, triglycerides, lipoproteins and bile acids were measured throughout the course of treatment. When hyperlipoproteinemias were divided according to phenotypes, type II hyperlipoproteinemia proved to be most commonly occurring (65.8%). The patients exhibited lower blood serum levels of bile acids as compared to control.

  3. AP-1 Inhibition by SR 11302 Protects Human Hepatoma HepG2 Cells from Bile Acid-Induced Cytotoxicity by Restoring the NOS-3 Expression

    PubMed Central

    González-Rubio, Sandra; Linares, Clara I.; Aguilar-Melero, Patricia; Rodríguez-Perálvarez, Manuel; Montero-Álvarez, José L.

    2016-01-01

    The harmful effects of bile acid accumulation occurring during cholestatic liver diseases have been associated with oxidative stress increase and endothelial nitric oxide synthase (NOS-3) expression decrease in liver cells. We have previously reported that glycochenodeoxycholic acid (GCDCA) down-regulates gene expression by increasing SP1 binding to the NOS-3 promoter in an oxidative stress dependent manner. In the present study, we aimed to investigate the role of transcription factor (TF) AP-1 on the NOS-3 deregulation during GCDCA-induced cholestasis. The cytotoxic response to GCDCA was characterized by 1) the increased expression and activation of TFs cJun and c-Fos; 2) a higher binding capability of these at position -666 of the NOS-3 promoter; 3) a decrease of the transcriptional activity of the promoter and the expression and activity of NOS-3; and 4) the expression increase of cyclin D1. Specific inhibition of AP-1 by the retinoid SR 11302 counteracted the cytotoxic effects induced by GCDCA while promoting NOS-3 expression recovery and cyclin D1 reduction. NOS activity inhibition by L-NAME inhibited the protective effect of SR 11302. Inducible NOS isoform was no detected in this experimental model of cholestasis. Our data provide direct evidence for the involvement of AP-1 in the NOS-3 expression regulation during cholestasis and define a critical role for NOS-3 in regulating the expression of cyclin D1 during the cell damage induced by bile acids. AP-1 appears as a potential therapeutic target in cholestatic liver diseases given its role as a transcriptional repressor of NOS-3. PMID:27490694

  4. Topical penetration of commercial salicylate esters and salts using human isolated skin and clinical microdialysis studies

    PubMed Central

    Cross, Sheree E; Anderson, Chris; Roberts, Michael S

    1998-01-01

    Aims The penetration of active ingredients from topically applied anti-inflammatory pharmaceutical products into tissues below the skin is the basis of their therapeutic efficacy. There is still controversy as to whether these agents are capable of direct penetration by diffusion through the tissues or whether redistribution in the systemic circulation is responsible for their tissue deposition below the application site. Methods The extent of direct penetration of salicylate from commercial ester and salt formulations into the dermal and subcutaneous tissue of human volunteers was determined using the technique of cutaneous microdialysis. We also examined differences in the extent of hydrolysis of the methylester of salicylate applied topically in human volunteers and in vitro skin diffusion cells using full-thickness skin and epidermal membranes. Results The present study showed that whilst significant levels of salicylate could be detected in the dermis and subcutaneous tissue of volunteers treated with the methylsalicylate formulation, negligible levels of salicylate were seen following application of the triethanolamine salicylate formulation. The tissue levels of salicylate from the methylsalicylate formulation were approx. 30-fold higher than the plasma concentrations. Conclusion The absorption and tissue concentration profiles for the commercial methylsalicylate formulation are indicative of direct tissue penetration and not solely redistribution by the systemic blood supply. PMID:9690946

  5. Bile Acid Responses in Methane and Non-Methane Producers to Standard Breakfast Meals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acids and their conjugates are important regulators of glucose homeostasis. Previous research has revealed the ratio of cholic acid to deoxycholic acid to affect insulin resistance in humans. Bile acid de-conjugation and intestinal metabolism depend on gut microbes which may be affected by hos...

  6. Xenobiotic, bile acid, and cholesterol transporters: function and regulation.

    PubMed

    Klaassen, Curtis D; Aleksunes, Lauren M

    2010-03-01

    Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting beta polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) alpha and beta] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of

  7. Xenobiotic, Bile Acid, and Cholesterol Transporters: Function and Regulation

    PubMed Central

    Aleksunes, Lauren M.

    2010-01-01

    Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting β polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) α and β] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory

  8. Th17/Treg Imbalance Induced by Dietary Salt Variation Indicates Inflammation of Target Organs in Humans

    PubMed Central

    Luo, Tao; Ji, Wen-jie; Yuan, Fei; Guo, Zhao-zeng; Li, Yun-xiao; Dong, Yan; Ma, Yong-qiang; Zhou, Xin; Li, Yu-ming

    2016-01-01

    The functions of T helper 17 (Th17) and regulatory T (Treg) cells are tightly orchestrated through independent differentiation pathways that are involved in the secretion of pro- and anti-inflammatory cytokines induced by high-salt dietary. However, the role of imbalanced Th17/Treg ratio implicated in inflammation and target organ damage remains elusive. Here, by flow cytometry analysis, we demonstrated that switching to a high-salt diet resulted in decreased Th17 cells and reciprocally increased Treg cells, leading to a decreased Th17/Treg ratio. Meanwhile, Th17-related pathway was down-regulated after one day of high salt loading, with the increase in high salt loading as shown by microarray and RT-PCR. Subsequently, blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) observed hypoxia in the renal medulla (increased R2* signal) during high-salt loading, which was regressed to its baseline level in a step-down fashion during low-salt feeding. The flow-mediated vasodilatation (FMD) of the branchial artery was significantly higher on the first day of high salt loading. Collectively, these observations indicate that a short-term increase in dietary salt intake could induce reciprocal switches in Th17/Treg ratio and related cytokines, which might be the underlying cellular mechanism of high-salt dietary induced end organ inflammation and potential atherosclerotic risk. PMID:27353721

  9. Chronic intermittent psychological stress promotes macrophage reverse cholesterol transport by impairing bile acid absorption in mice

    PubMed Central

    Silvennoinen, Reija; Quesada, Helena; Kareinen, Ilona; Julve, Josep; Kaipiainen, Leena; Gylling, Helena; Blanco-Vaca, Francisco; Escola-Gil, Joan Carles; Kovanen, Petri T; Lee-Rueckert, Miriam

    2015-01-01

    Psychological stress is a risk factor for atherosclerosis, yet the pathophysiological mechanisms involved remain elusive. The transfer of cholesterol from macrophage foam cells to liver and feces (the macrophage-specific reverse cholesterol transport, m-RCT) is an important antiatherogenic pathway. Because exposure of mice to physical restraint, a model of psychological stress, increases serum levels of corticosterone, and as bile acid homeostasis is disrupted in glucocorticoid-treated animals, we investigated if chronic intermittent restraint stress would modify m-RCT by altering the enterohepatic circulation of bile acids. C57Bl/6J mice exposed to intermittent stress for 5 days exhibited increased transit through the large intestine and enhanced fecal bile acid excretion. Of the transcription factors and transporters that regulate bile acid homeostasis, the mRNA expression levels of the hepatic farnesoid X receptor (FXR), the bile salt export pump (BSEP), and the intestinal fibroblast growth factor 15 (FGF15) were reduced, whereas those of the ileal apical sodium-dependent bile acid transporter (ASBT), responsible for active bile acid absorption, remained unchanged. Neither did the hepatic expression of cholesterol 7α-hydroxylase (CYP7A1), the key enzyme regulating bile acid synthesis, change in the stressed mice. Evaluation of the functionality of the m-RCT pathway revealed increased fecal excretion of bile acids that had been synthesized from macrophage-derived cholesterol. Overall, our study reveals that chronic intermittent stress in mice accelerates m-RCT specifically by increasing fecal excretion of bile acids. This novel mechanism of m-RCT induction could have antiatherogenic potential under conditions of chronic stress. PMID:25969465

  10. Fifty years with bile acids and steroids in health and disease.

    PubMed

    Sjövall, Jan

    2004-08-01

    Cholesterol and its metabolites, e.g., steroid hormones and bile acids, constitute a class of compounds of great biological importance. Their chemistry, biochemistry, and regulation in the body have been intensely studied for more than two centuries. The author has studied aspects of the biochemistry and clinical chemistry of steroids and bile acids for more than 50 years, and this paper, which is an extended version of the Schroepfer Medal Award lecture, reviews and discusses part of this work. Development and application of analytical methods based on chromatography and mass spectrometry (MS) have been a central part of many projects, aiming at detailed characterization and quantification of metabolic profiles of steroids and bile acids under different conditions. In present terminology, much of the work may be termed steroidomics and cholanoidomics. Topics discussed are bile acids in human bile and feces, bile acid production, bacterial dehydroxylation of bile acids and steroids during the enterohepatic circulation, profiles of steroid sulfates in plasma of humans and other primates, development of neutral and ion-exchanging lipophilic derivatives of Sephadex for sample preparation and group separation of steroid and bile acid conjugates, profiles of steroids and bile acids in human urine under different conditions, hydroxylation of bile acids in liver disease, effects of alcohol-induced redox changes on steroid synthesis and metabolism, alcohol-induced changes of bile acid biosynthesis, compartmentation of bile acid synthesis studied with 3H-labeled ethanol, formation and metabolism of sulfated metabolites of progesterone in human pregnancy, abnormal patterns of these in patients with intrahepatic cholestasis of pregnancy corrected by ursodeoxycholic acid, inherited and acquired defects of bile acid biosynthesis and their treatment, conjugation of bile acids and steroids with N-acetylglucosamine, sulfate-glucuronide double conjugates of hydroxycholesterols

  11. Laparoscopic common bile duct exploration.

    PubMed

    Vecchio, Rosario; MacFadyen, Bruce V

    2002-04-01

    In recent years, laparoscopic common bile duct exploration has become the procedure of choice in the management of choledocholithiasis in several laparoscopic centers. The increasing interest for this laparoscopic approach is due to the development of instrumentation and technique, allowing the procedure to be performed safely, and it is also the result of the revised role of endoscopic retrograde cholangiopancreatography, which has been questioned because of its cost, risk of complications and effectiveness. Many surgeons, however, are still not familiar with this technique. In this article we discuss the technique and results of laparoscopic common bile duct exploration. Both the laparoscopic transcystic approach and choledochotomy are discussed, together with the results given in the literature. When one considers the costs, morbidity, mortality and the time required before the patient can return to work, it would appear that laparoscopic cholecystectomy with common bile duct exploration is more favorable than open surgery or laparoscopic cholecystectomy with preoperative or postoperative endoscopic sphincterotomy. However, the technique requires advanced laparoscopic skills, including suturing, knot tying, the use of a choledochoscope, guidewire, dilators and balloon stone extractor. Although laparoscopic common bile duct exploration appears to be the most cost-effective method to treat common bile duct stones, it should be emphasized that this procedure is very challenging, and it should be performed by well-trained laparoscopic surgeons with experience in biliary surgery. PMID:11981684

  12. Protocols for staining of bile canalicular and sinusoidal networks of human, mouse and pig livers, three-dimensional reconstruction and quantification of tissue microarchitecture by image processing and analysis.

    PubMed

    Hammad, Seddik; Hoehme, Stefan; Friebel, Adrian; von Recklinghausen, Iris; Othman, Amnah; Begher-Tibbe, Brigitte; Reif, Raymond; Godoy, Patricio; Johann, Tim; Vartak, Amruta; Golka, Klaus; Bucur, Petru O; Vibert, Eric; Marchan, Rosemarie; Christ, Bruno; Dooley, Steven; Meyer, Christoph; Ilkavets, Iryna; Dahmen, Uta; Dirsch, Olaf; Böttger, Jan; Gebhardt, Rolf; Drasdo, Dirk; Hengstler, Jan G

    2014-05-01

    parameters in adult mice (C57Bl6/N) include the hepatocyte volume (5,128.3 ± 837.8 μm(3)) and the fraction of the hepatocyte surface in contact with the neighbouring hepatocytes (67.4 ± 6.7 %), sinusoids (22.1 ± 4.8 %) and bile canaliculi (9.9 ± 3.8 %). Parameters of the sinusoidal network that we also routinely quantify include the radius of the sinusoids (4.8 ± 2.25 μm), the branching angle (32.5 ± 11.2°), the length of intersection branches (23.93 ± 5.9 μm), the number of intersection nodes per mm(3) (120.3 × 103 ± 42.1 × 10(3)), the average length of sinusoidal vessel per mm(3) (5.4 × 10(3) ± 1.4 × 10(3)mm) and the percentage of vessel volume in relation to the whole liver volume (15.3 ± 3.9) (mean ± standard deviation). Moreover, the provided parameters of the bile canalicular network are: length of the first-order branches (7.5 ± 0.6 μm), length of the second-order branches (10.9 ± 1.8 μm), length of the dead-end branches (5.9 ± 0.7 μm), the number of intersection nodes per mm(3) (819.1 × 10(3) ± 180.7 × 10(3)), the number of dead-end branches per mm(3) (409.9 × 10(3) ± 95.6 × 10(3)), the length of the bile canalicular network per mm(3) (9.4 × 10(3) ± 0.7 × 10(3) mm) and the percentage of the bile canalicular volume with respect to the total liver volume (3.4 ± 0.005). A particular strength of our technique is that quantitative parameters of hepatocytes and bile canalicular as well as sinusoidal networks can be extracted from the same tissue block. Reconstructions and quantifications performed as described in the current protocols can be used for quantitative mathematical modelling of the underlying mechanisms. Furthermore, protocols are presented for both human and pig livers. The technique is also applicable for both vibratome blocks and conventional paraffin slices. PMID:24748404

  13. Protocols for staining of bile canalicular and sinusoidal networks of human, mouse and pig livers, three-dimensional reconstruction and quantification of tissue microarchitecture by image processing and analysis.

    PubMed

    Hammad, Seddik; Hoehme, Stefan; Friebel, Adrian; von Recklinghausen, Iris; Othman, Amnah; Begher-Tibbe, Brigitte; Reif, Raymond; Godoy, Patricio; Johann, Tim; Vartak, Amruta; Golka, Klaus; Bucur, Petru O; Vibert, Eric; Marchan, Rosemarie; Christ, Bruno; Dooley, Steven; Meyer, Christoph; Ilkavets, Iryna; Dahmen, Uta; Dirsch, Olaf; Böttger, Jan; Gebhardt, Rolf; Drasdo, Dirk; Hengstler, Jan G

    2014-05-01

    parameters in adult mice (C57Bl6/N) include the hepatocyte volume (5,128.3 ± 837.8 μm(3)) and the fraction of the hepatocyte surface in contact with the neighbouring hepatocytes (67.4 ± 6.7 %), sinusoids (22.1 ± 4.8 %) and bile canaliculi (9.9 ± 3.8 %). Parameters of the sinusoidal network that we also routinely quantify include the radius of the sinusoids (4.8 ± 2.25 μm), the branching angle (32.5 ± 11.2°), the length of intersection branches (23.93 ± 5.9 μm), the number of intersection nodes per mm(3) (120.3 × 103 ± 42.1 × 10(3)), the average length of sinusoidal vessel per mm(3) (5.4 × 10(3) ± 1.4 × 10(3)mm) and the percentage of vessel volume in relation to the whole liver volume (15.3 ± 3.9) (mean ± standard deviation). Moreover, the provided parameters of the bile canalicular network are: length of the first-order branches (7.5 ± 0.6 μm), length of the second-order branches (10.9 ± 1.8 μm), length of the dead-end branches (5.9 ± 0.7 μm), the number of intersection nodes per mm(3) (819.1 × 10(3) ± 180.7 × 10(3)), the number of dead-end branches per mm(3) (409.9 × 10(3) ± 95.6 × 10(3)), the length of the bile canalicular network per mm(3) (9.4 × 10(3) ± 0.7 × 10(3) mm) and the percentage of the bile canalicular volume with respect to the total liver volume (3.4 ± 0.005). A particular strength of our technique is that quantitative parameters of hepatocytes and bile canalicular as well as sinusoidal networks can be extracted from the same tissue block. Reconstructions and quantifications performed as described in the current protocols can be used for quantitative mathematical modelling of the underlying mechanisms. Furthermore, protocols are presented for both human and pig livers. The technique is also applicable for both vibratome blocks and conventional paraffin slices.

  14. Bile components and amino acids affect survival of the newly excysted juvenile Clonorchis sinensis in maintaining media.

    PubMed

    Li, Shunyu; Kim, Tae Im; Yoo, Won Gi; Cho, Pyo Yun; Kim, Tong-Soo; Hong, Sung-Jong

    2008-10-01

    Clonorchis sinensis thrives on bile juice. The effects of bile and bile acids on newly excysted juvenile C. sinensis (CsNEJ) were studied in terms of survival. Survival of CsNEJs maintained in 1x Locke's solution, Dulbecco's modified Eagle's medium, NCTC 109, Eagle's, RPMI 1640, and 0.1% glucose was high, but dropped rapidly in 2x Locke's, 0.85% NaCl, and phosphate-buffered saline. Most amino acids in the media favored CsNEJ survival; however, aspartic and glutamic acids and adenine reduced survival. Survival was also significantly lower in media containing more than 0.1% bile. CsNEJs preconditioned in low bile media survived longer in higher bile media. All bile acids and conjugated bile salts were found to favor CsNEJ survival, except for lithocholic acid (LCA) which was toxic. NCTC 109 medium was found to be optimal for the in vitro maintenance of CsNEJs and 1x Locke's solution to be suitable for analyzing the biological effects of bioactive compounds and molecules. Based on these results, we propose that bile acids enhance activity of CsNEJs, but LCA deteriorate CsNEJs.

  15. Evidence for plasmid-mediated salt tolerance in the human gut microbiome and potential mechanisms.

    PubMed

    Broaders, Eileen; O'Brien, Ciarán; Gahan, Cormac G M; Marchesi, Julian R

    2016-03-01

    The human gut microbiome is critical to health and wellbeing. It hosts a complex ecosystem comprising a multitude of bacterial species, which contributes functionality that would otherwise be absent from the host. Transient and commensal bacteria in the gut must withstand many stresses. The influence of mobile genetic elements such as plasmids in stress adaptation within the ecosystem is poorly understood. Using a mobilomic approach we found evidence for plasmid-mediated osmotolerance as a phenotype amongst the Proteobacteria in healthy faecal slurries. A transconjugant carrying multiple plasmids acquired from healthy faecal slurry demonstrated increased osmotolerance in the presence of metal salts, particularly potassium chloride, which was not evident in the recipient. Pyrosequencing and analysis of the total plasmid DNA demonstrated the presence of plasmid-borne osmotolerance systems (including KdpD and H-NS) which may be linked to the observed phenotype. This is the first report of a transferable osmotolerance phenotype in gut commensals and may have implications for the transfer of osmotolerance in other niches.

  16. Mediators of exocrine pancreatic secretion induced by intraduodenal application of bile and taurodeoxycholate in man.

    PubMed

    Riepl, R L; Reichardt, B; Rauscher, J; Tzavella, K; Teufel, J; Lehnert, P

    1997-01-01

    The aim of the study was to investigate whether cholecystokinin, neurotensin, and cholinergic mechanisms act as mediators of bile salt-stimulated exocrine pancreatic secretion. Ten fasting healthy subjects provided with a double-lumen tube received 2, 4, and 6 g cattle bile and 200, 400, and 600 mg Na-taurodeoxycholate (TDC) into the duodenum at 65-min intervals, respectively. The application of TDC was repeated in another 10 subjects after intravenous bolus injection of 2.5 micrograms/kg b.w. atropine followed by continuous infusion of 5 micrograms/kg.h. Secretions of volume, bicarbonate, trypsin, and lipase were determined in 10-min fractions of duodenal juice. Plasma samples were analysed for cholecystokinin-like immunoreactivity (CCK-LI) and neurotensin with radioimmunoassays. Volume, bicarbonate, trypsin, and lipase secretion rates were significantly increased by 4 g and 6 g bile and by all doses of TDC. Incremental volume and bicarbonate output was dose-dependently enhanced by bile and TDC, and trypsin and lipase output by bile. Atropine significantly decreased the baseline values and all responses to TDC. Plasma concentrations and integrated CCK-LI and neurotensin significantly increased after 4 and 6 g bile and after 400 and 600 mg TDC. Atropine did not significantly influence peptide release. It is concluded that both hydrokinetic and ecbolic pancreatic secretion stimulated by intraduodenal bile and TDC are dependent on a cholinergic tone. CCK and probably also neurotensin act as further mediators of the ecbolic effect.

  17. Mediators of exocrine pancreatic secretion induced by intraduodenal application of bile and taurodeoxycholate in man.

    PubMed

    Riepl, R L; Reichardt, B; Rauscher, J; Tzavella, K; Teufel, J; Lehnert, P

    1997-01-01

    The aim of the study was to investigate whether cholecystokinin, neurotensin, and cholinergic mechanisms act as mediators of bile salt-stimulated exocrine pancreatic secretion. Ten fasting healthy subjects provided with a double-lumen tube received 2, 4, and 6 g cattle bile and 200, 400, and 600 mg Na-taurodeoxycholate (TDC) into the duodenum at 65-min intervals, respectively. The application of TDC was repeated in another 10 subjects after intravenous bolus injection of 2.5 micrograms/kg b.w. atropine followed by continuous infusion of 5 micrograms/kg.h. Secretions of volume, bicarbonate, trypsin, and lipase were determined in 10-min fractions of duodenal juice. Plasma samples were analysed for cholecystokinin-like immunoreactivity (CCK-LI) and neurotensin with radioimmunoassays. Volume, bicarbonate, trypsin, and lipase secretion rates were significantly increased by 4 g and 6 g bile and by all doses of TDC. Incremental volume and bicarbonate output was dose-dependently enhanced by bile and TDC, and trypsin and lipase output by bile. Atropine significantly decreased the baseline values and all responses to TDC. Plasma concentrations and integrated CCK-LI and neurotensin significantly increased after 4 and 6 g bile and after 400 and 600 mg TDC. Atropine did not significantly influence peptide release. It is concluded that both hydrokinetic and ecbolic pancreatic secretion stimulated by intraduodenal bile and TDC are dependent on a cholinergic tone. CCK and probably also neurotensin act as further mediators of the ecbolic effect. PMID:9049590

  18. Bile tolerance and its effect on antibiotic susceptibility of probiotic Lactobacillus candidates.

    PubMed

    Hyacinta, Májeková; Hana, Kiňová Sepová; Andrea, Bilková; Barbora, Čisárová

    2015-05-01

    Before use in practice, it is necessary to precisely identify and characterize a new probiotic candidate. Eight animal lactobacilli and collection strain Lactobacillus reuteri CCM 3625 were studied from the point of saccharide fermentation profiles, bile salt resistance, antibiogram profiles, and influence of bile on sensitivity to antibiotics. Studied lactobacilli differed in their sugar fermentation ability determined by API 50CHL and their identification based on these profiles did not correspond with molecular-biological one in most cases. Survival of strains Lactobacillus murinus C and L. reuteri KO4b was not affected by presence of bile. The resistance of genus Lactobacillus to vancomycin and quinolones (ofloxacin, ciprofloxacin) was confirmed in all strains tested. This study provides the new information about oxgall (0.5 and 1 %) effect on the lactobacilli antibiotic susceptibility. Antibiotic profiles were not noticeably affected, and both bile concentrations tested had comparable impact on the lactobacilli antibiotic sensitivity. Interesting change was noticed in L. murinus C, where the resistance to cephalosporins was reverted to susceptibility. Similarly, susceptibility of L. reuteri E to ceftazidime arose after incubation in both concentration of bile. After influence of 1 % bile, Lactobacillus mucosae D lost its resistance to gentamicin. On the base of gained outcomes, the best probiotic properties manifested L. reuteri KO4b, Lactobacillus plantarum KG4, and L. reuteri E due to their survival in the presence of bile.

  19. What's New in Bile Duct Cancer Research and Treatment?

    MedlinePlus

    ... Topic Additional resources for bile duct cancer What’s new in bile duct cancer research and treatment? Bile ... is tumor blood vessels. Bile duct tumors need new blood vessels to grow beyond a certain size. ...

  20. Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis

    PubMed Central

    Gomez-Ospina, Natalia; Potter, Carol J.; Xiao, Rui; Manickam, Kandamurugu; Kim, Mi-Sun; Kim, Kang Ho; Shneider, Benjamin L.; Picarsic, Jennifer L.; Jacobson, Theodora A.; Zhang, Jing; He, Weimin; Liu, Pengfei; Knisely, A. S.; Finegold, Milton J.; Muzny, Donna M.; Boerwinkle, Eric; Lupski, James R.; Plon, Sharon E.; Gibbs, Richard A.; Eng, Christine M.; Yang, Yaping; Washington, Gabriel C.; Porteus, Matthew H.; Berquist, William E.; Kambham, Neeraja; Singh, Ravinder J.; Xia, Fan; Enns, Gregory M.; Moore, David D.

    2016-01-01

    Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection. PMID:26888176

  1. Proteomic and transcriptomic analysis of the response to bile stress of Lactobacillus casei BL23.

    PubMed

    Alcántara, Cristina; Zúñiga, Manuel

    2012-05-01

    Lactobacillus casei is a lactic acid bacterium commonly found in the gastrointestinal tract of animals, and some strains are used as probiotics. The ability of probiotic strains to survive the passage through the gastrointestinal tract is considered a key factor for their probiotic action. Therefore, tolerance to bile salts is a desirable feature for probiotic strains. In this study we have characterized the response of L. casei BL23 to bile by a transcriptomic and proteomic approach. The analysis revealed that exposure to bile induced changes in the abundance of 52 proteins and the transcript levels of 67 genes. The observed changes affected genes and proteins involved in the stress response, fatty acid and cell wall biosynthesis, metabolism of carbohydrates, transport of peptides, coenzyme levels, membrane H(+)-ATPase, and a number of uncharacterized genes and proteins. These data provide new insights into the mechanisms that enable L. casei BL23 to cope with bile stress. PMID:22322960

  2. Knockdown of ATP8B1 expression leads to specific downregulation of the bile acid sensor FXR in HepG2 cells: effect of the FXR agonist GW4064.

    PubMed

    Martínez-Fernández, Pilar; Hierro, Loreto; Jara, Paloma; Alvarez, Luis

    2009-05-01

    Farnesoid X receptor (FXR) is a bile acid-sensing nuclear receptor that controls bile acid homeostasis. It has been suggested that downregulation of FXR contributes to the pathogenesis of an inherited disorder of bile secretion caused by mutations in ATP8B1. We have investigated the relationship between ATP8B1 knockdown and FXR downregulation in the human hepatoblastoma cell line HepG2. Transfection of HepG2 cells with ATP8B1 small interfering RNA (siRNA) duplexes led to a 60% reduction in the endogenous levels of ATP8B1 mRNA and protein and a concomitant decrease in FXR mRNA and protein content, as well as in FXR phosphorylation. This decrease was accompanied by a marked reduction in mRNA levels of a subset of FXR targets, such as bile salt export pump (ABCB11), small heterodimer partner, and uridine 5'-diphosphate-glucuronosyltransferase. ATP8B1 inhibition specifically targeted FXR since mRNA expression of other prominent nuclear receptors, such as pregnane X receptor and constitutive androstane receptor, or liver-enriched transcription factors, such as hepatocyte nuclear factor 1alpha (HNF-1alpha) and HNF-4alpha, was not altered. The expression of other key genes involved in bile acid synthesis, detoxification, and transport also remained unchanged upon ATP8B1 knockdown. Supporting the specificity of the effect, siRNA-mediated silencing of ABCB11, whose defect is associated with another inherited disorder of bile secretion, did not affect FXR expression. Treatment with the synthetic FXR agonist GW4064 was able to partially neutralize ATP8B1 siRNA-mediated FXR downregulation and fully counteract inhibition of FXR target genes. Collectively these findings indicate that ATP8B1 knockdown specifically downregulates FXR, and this action can be circumvented by treatment with FXR agonists.

  3. Gut microbiota, cirrhosis and alcohol regulate bile acid metabolism in the gut

    PubMed Central

    Ridlon, Jason M.; Kang, Dae-Joong; Hylemon, Phillip B.; Bajaj, Jasmohan S

    2015-01-01

    The understanding of the complex role of the bile acid-gut microbiome axis in health and disease processes is evolving rapidly. Our focus revolves around the interaction of the gut microbiota with liver diseases, especially cirrhosis. The bile acid pool size has recently been shown to be a function of microbial metabolism of bile acid and regulation of the microbiota by bile acids is important in the development and progression of several liver diseases. Humans produce a large, conjugated hydrophilic bile acid pool, maintained through positive-feedback antagonism of FXR in intestine and liver. Microbes use bile acids, and via FXR signaling this results in a smaller, unconjugated hydrophobic bile acid pool. This equilibrium is critical to maintain health. The challenge is to examine the manifold functions of gut bile acids as modulators of antibiotic, probiotic and disease progression in cirrhosis, metabolic syndrome and alcohol use. Recent studies have shown potential mechanisms explaining how perturbations in the microbiome affect bile acid pool size and composition. With advancing liver disease and cirrhosis, there is dysbiosis in the fecal, ileal and colonic mucosa, in addition to a decrease in bile acid concentration in the intestine due to the liver problems. This results in a dramatic shift toward the Firmicutes, particularly Clostridium cluster XIVa and increasing production of deoxycholic acid (DCA). Alcohol intake speeds up these processes in the subjects with and without cirrhosis without significant FXR feedback. Taken together, these pathways can impact intestinal and systemic inflammation while worsening dysbiosis. The interaction between bile acids, alcohol, cirrhosis and dysbiosis is an important relationship that influences intestinal and systemic inflammation, which in turn determines progression of the overall disease process. These interactions and the impact of commonly used therapies for liver disease can provide insight into the pathogenesis

  4. Homologue gene of bile acid transporters ntcp, asbt, and ost-alpha in rainbow trout Oncorhynchus mykiss: tissue expression, effect of fasting, and response to bile acid administration.

    PubMed

    Murashita, Koji; Yoshiura, Yasutoshi; Chisada, Shin-Ichi; Furuita, Hirofumi; Sugita, Tsuyoshi; Matsunari, Hiroyuki; Iwashita, Yasuro; Yamamoto, Takeshi

    2014-04-01

    Bile acid transporters belonging to the SLC10A protein family, Na+ taurocholate cotransporting polypeptide (NTCP or SLC10A1), apical sodium-dependent bile salt transporter (ASBT or SLC10A2), and organic solute transporter alpha (Ost-alpha) have been known to play critical roles in the enterohepatic circulation of bile acids in mammals. In this study, ntcp, asbt, and ost-alpha-1/-2 cDNA were cloned, their tissue distributions were characterized, and the effects of fasting and bile acid administration on their expression were examined in rainbow trout Oncorhynchus mykiss. The structural characteristics of Ntcp, Asbt, and Ost-alpha were well conserved in trout, and three-dimensional structure analysis showed that Ntcp and Asbt were similar to each other. Tissue distribution analysis revealed that trout asbt was primarily expressed in the hindgut, while ntcp expression occurred in the brain, and ost-alpha-1/-2 was mainly expressed in the liver or ovary. Although asbt and ost-alpha-1 mRNA levels in the gut increased in response to fasting for 4 days, ost-alpha-1 expression in the liver decreased. Similarly, bile acid administration increased asbt and ost-alpha-1 expression levels in the gut, while those of ntcp and ost-alpha-2 in the liver decreased. These results suggested that the genes asbt, ntcp, and ost-alpha are involved in bile acid transport in rainbow trout.

  5. General Information about Extrahepatic Bile Duct Cancer

    MedlinePlus

    ... Bile Duct Cancer Treatment (PDQ®)–Patient Version General Information About Bile Duct Cancer Go to Health Professional ... the PDQ Adult Treatment Editorial Board . Clinical Trial Information A clinical trial is a study to answer ...

  6. Serum bile acids in hepatobiliary disease.

    PubMed Central

    Bouchier, I A; Pennington, C R

    1978-01-01

    We review the estimation of total and individual serum bile acids to detect the presence and nature of hepatobiliary disease. The different methods for measuring serum bile acids are discussed. PMID:355064

  7. Contributions of unfrozen fraction and of salt concentration to the survival of slowly frozen human erythrocytes: influence of warming rate

    SciTech Connect

    Mazur, P.; Rigopoulos, N.

    1983-01-01

    The general belief is that slow freezing injury is either the result of exposure to high salt concentrations or the result of excessive cell shrinkage. Ordinarily, salt concentration and the amount of liquid in the unfrozen channels are reciprocally related; but they can be separated within limits by varying the total concentration of solutes in the suspending medium while holding the mass ratio of additive to salt constant, and by then slowly freezing samples to various subzero temperatures. The authors have recently reported that when human red cells are frozen under these conditions and thawed rapidly, survival is more dependent on the unfrozen water fraction than it is on the salt concentration in that fraction. The present work compares these results with those obtained with slow thawing. While the general conclusion remains unaltered, slowly thawed cells were able to survive the freezing of a higher fraction of extracellular water than were rapidly thawed cells. Calculations were made of the changes in cell volume during the equilibration with glycerol and the subsequent freezing involved in these experiments.

  8. Multitask Imidazolium Salt Additives for Innovative Poly(l-lactide) Biomaterials: Morphology Control, Candida spp. Biofilm Inhibition, Human Mesenchymal Stem Cell Biocompatibility, and Skin Tolerance.

    PubMed

    Schrekker, Clarissa M L; Sokolovicz, Yuri C A; Raucci, Maria G; Selukar, Balaji S; Klitzke, Joice S; Lopes, William; Leal, Claudio A M; de Souza, Igor O P; Galland, Griselda B; Dos Santos, João Henrique Z; Mauler, Raquel S; Kol, Moshe; Dagorne, Samuel; Ambrosio, Luigi; Teixeira, Mário L; Morais, Jonder; Landers, Richard; Fuentefria, Alexandre M; Schrekker, Henri S

    2016-08-24

    Candida species have great ability to colonize and form biofilms on medical devices, causing infections in human hosts. In this study, poly(l-lactide) films with different imidazolium salt (1-n-hexadecyl-3-methylimidazolium chloride (C16MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16MImMeS)) contents were prepared, using the solvent casting process. Poly(l-lactide)-imidazolium salt films were obtained with different surface morphologies (spherical and directional), and the presence of the imidazolium salt in the surface was confirmed. These films with different concentrations of the imidazolium salts C16MImCl and C16MImMeS presented antibiofilm activity against isolates of Candida tropicalis, Candida parapsilosis, and Candida albicans. The minor antibiofilm concentration assay enabled one to determine that an increasing imidazolium salt content promoted, in general, an increase in the inhibition percentage of biofilm formation. Scanning electron microscopy micrographs confirmed the effective prevention of biofilm formation on the imidazolium salt containing biomaterials. Lower concentrations of the imidazolium salts showed no cytotoxicity, and the poly(l-lactide)-imidazolium salt films presented good cell adhesion and proliferation percentages with human mesenchymal stem cells. Furthermore, no acute microscopic lesions were identified in the histopathological evaluation after contact between the films and pig ear skin. In combination with the good morphological, physicochemical, and mechanical properties, these poly(l-lactide)-based materials with imidazolium salt additives can be considered as promising biomaterials for use in the manufacturing of medical devices.

  9. Concept of double salt fortification; a tool to curtail micronutrient deficiencies and improve human health status.

    PubMed

    Sultan, Saira; Anjum, Faqir Muhammad; Butt, Masood Sadiq; Huma, Nuzhat; Suleria, Hafiz Ansar Rasul

    2014-11-01

    Fortification of food with micronutrients such as vitamins and minerals is one of the main strategies used to combat micronutrient deficiencies. Fortification in common salt is a fruitful strategy because of the daily consumption of 5-12 g salt per person globally. Therefore double fortification of salt with iodine and iron could be a reasonable approach to prevent both iodine and iron deficiencies. It is reckoned that about two billion people are iodine-deficient worldwide. Iodine deficiency during pregnancy may affect the health status of both mother and fetus and increase infant mortality. Deficiencies of both these micronutrients during childhood affect somatic growth and cognitive and neurological function. Thyroid metabolism is negatively affected by iron deficiency and reduced effectiveness of iodine prophylaxis in areas of endemic goiter. High prevalence of iron deficiency among children may be reduced by the application of effective iodized salt programs. However, ensuring the stability and bioavailability of both iron and iodine as double-fortified salt is difficult. Iodine present in iodide or iodate form in dual-fortified salt is oxidized to free iodine in the presence of ferrous ions and oxygen and consequently loses its characteristics. Moreover, ferrous iron is more bioavailable but is readily oxidized to the less bioavailable ferric form. However, both forms of iron may lead to discoloration of the final product, which can be reduced by providing a physical barrier around the iron. Salt encapsulation is one of the best tools to provide a physical barrier for undesirable reactions and interactions during storage. In this review the concept of dual salt fortification, the impact of fortification on curing various life-threatening maladies, latest assessments of mineral deficiencies and the choice of fortificants are discussed.

  10. Repression of Salmonella enterica phoP expression by small molecules from physiological bile.

    PubMed

    Antunes, L Caetano M; Wang, Melody; Andersen, Sarah K; Ferreira, Rosana B R; Kappelhoff, Reinhild; Han, Jun; Borchers, Christoph H; Finlay, B Brett

    2012-05-01

    Infection with Salmonella enterica serovar Typhi in humans causes the life-threatening disease typhoid fever. In the laboratory, typhoid fever can be modeled through the inoculation of susceptible mice with Salmonella enterica serovar Typhimurium. Using this murine model, we previously characterized the interactions between Salmonella Typhimurium and host cells in the gallbladder and showed that this pathogen can successfully invade gallbladder epithelial cells and proliferate. Additionally, we showed that Salmonella Typhimurium can use bile phospholipids to grow at high rates. These abilities are likely important for quick colonization of the gallbladder during typhoid fever and further pathogen dissemination through fecal shedding. To further characterize the interactions between Salmonella and the gallbladder environment, we compared the transcriptomes of Salmonella cultures grown in LB broth or physiological murine bile. Our data showed that many genes involved in bacterial central metabolism are affected by bile, with the citric acid cycle being repressed and alternative respiratory systems being activated. Additionally, our study revealed a new aspect of Salmonella interactions with bile through the identification of the global regulator phoP as a bile-responsive gene. Repression of phoP expression could also be achieved using physiological, but not commercial, bovine bile. The biological activity does not involve PhoPQ sensing of a bile component and is not caused by bile acids, the most abundant organic components of bile. Bioactivity-guided purification allowed the identification of a subset of small molecules from bile that can elicit full activity; however, a single compound with phoP inhibitory activity could not be isolated, suggesting that multiple molecules may act in synergy to achieve this effect. Due to the critical role of phoP in Salmonella virulence, further studies in this area will likely reveal aspects of the interaction between Salmonella

  11. Oral administration of Bifidobacterim bifidum for modulating microflora, acid and bile resistance, and physiological indices in mice.

    PubMed

    Wang, Bao-Gui; Xu, Hai-Bo; Wei, Hua; Zeng, Zhe-Ling; Xu, Feng

    2015-02-01

    Bifidobacteria are generally acknowledged as major gut microflora used as probiotics, which promote human health. In this study, the effects of the administration of Bifidobacterim bifidum on modulating gastrointestinal (GI) tract microflora, acid and bile resistance, and physiological indices in BALB/c mice were investigated. Results showed that B. bifidum can significantly improve the ecosystem of the GI tract by increasing the amount of probiotics and reducing the populations of pathogenic bacteria, as measured by plate count and real-time PCR. After exposure to simulated GI tract conditions, the growth of gut microflora in the B. bifidum group was higher than that in the control group when incubated for 12 h in MRS or nutrient broth adjusted to pH 2.0 or 3.0 or in the presence of a concentration of bile salt (0.45% m/v). The blood biochemical index was examined, and the physiological effect of the cell-free extract of gut microflora was evaluated by measuring the activity of various enzymes, including α-glucosidases, esterase, and lactate dehydrogenase. This study suggested that a B. bifidum strain can stabilize blood sugar, lower cholesterol levels in serum, and improve metabolic activity. Moreover, B. bifidum was a promising enhancer of microbial diversity in mouse intestine and played a vital role in human physiological processes, which can benefit the health of a host. PMID:25630400

  12. Oral administration of Bifidobacterim bifidum for modulating microflora, acid and bile resistance, and physiological indices in mice.

    PubMed

    Wang, Bao-Gui; Xu, Hai-Bo; Wei, Hua; Zeng, Zhe-Ling; Xu, Feng

    2015-02-01

    Bifidobacteria are generally acknowledged as major gut microflora used as probiotics, which promote human health. In this study, the effects of the administration of Bifidobacterim bifidum on modulating gastrointestinal (GI) tract microflora, acid and bile resistance, and physiological indices in BALB/c mice were investigated. Results showed that B. bifidum can significantly improve the ecosystem of the GI tract by increasing the amount of probiotics and reducing the populations of pathogenic bacteria, as measured by plate count and real-time PCR. After exposure to simulated GI tract conditions, the growth of gut microflora in the B. bifidum group was higher than that in the control group when incubated for 12 h in MRS or nutrient broth adjusted to pH 2.0 or 3.0 or in the presence of a concentration of bile salt (0.45% m/v). The blood biochemical index was examined, and the physiological effect of the cell-free extract of gut microflora was evaluated by measuring the activity of various enzymes, including α-glucosidases, esterase, and lactate dehydrogenase. This study suggested that a B. bifidum strain can stabilize blood sugar, lower cholesterol levels in serum, and improve metabolic activity. Moreover, B. bifidum was a promising enhancer of microbial diversity in mouse intestine and played a vital role in human physiological processes, which can benefit the health of a host.

  13. Steam cooking significantly improves in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage.

    PubMed

    Kahlon, Talwinder Singh; Chiu, Mei-Chen M; Chapman, Mary H

    2008-06-01

    Bile acid binding capacity has been related to the cholesterol-lowering potential of foods and food fractions. Lowered recirculation of bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increased risk of cancer. Bile acid binding potential has been related to lowering the risk of heart disease and that of cancer. Previously, we have reported bile acid binding by several uncooked vegetables. However, most vegetables are consumed after cooking. How cooking would influence in vitro bile acid binding of various vegetables was investigated using a mixture of bile acids secreted in human bile under physiological conditions. Eight replicate incubations were conducted for each treatment simulating gastric and intestinal digestion, which included a substrate only, a bile acid mixture only, and 6 with substrate and bile acid mixture. Cholestyramine (a cholesterol-lowering, bile acid binding drug) was the positive control treatment and cellulose was the negative control. Relative to cholestyramine, in vitro bile acid binding on dry matter basis was for the collard greens, kale, and mustard greens, 13%; broccoli, 10%; Brussels sprouts and spinach, 8%; green bell pepper, 7%; and cabbage, 5%. These results point to the significantly different (P < or = .05) health-promoting potential of collard greens = kale = mustard greens > broccoli > Brussels sprouts = spinach = green bell pepper > cabbage as indicated by their bile acid binding on dry matter basis. Steam cooking significantly improved the in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage compared with previously observed bile acid binding values for these vegetables raw (uncooked). Inclusion of steam-cooked collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage in our daily diet as health-promoting vegetables should be emphasized. These green

  14. Steam cooking significantly improves in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage.

    PubMed

    Kahlon, Talwinder Singh; Chiu, Mei-Chen M; Chapman, Mary H

    2008-06-01

    Bile acid binding capacity has been related to the cholesterol-lowering potential of foods and food fractions. Lowered recirculation of bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increased risk of cancer. Bile acid binding potential has been related to lowering the risk of heart disease and that of cancer. Previously, we have reported bile acid binding by several uncooked vegetables. However, most vegetables are consumed after cooking. How cooking would influence in vitro bile acid binding of various vegetables was investigated using a mixture of bile acids secreted in human bile under physiological conditions. Eight replicate incubations were conducted for each treatment simulating gastric and intestinal digestion, which included a substrate only, a bile acid mixture only, and 6 with substrate and bile acid mixture. Cholestyramine (a cholesterol-lowering, bile acid binding drug) was the positive control treatment and cellulose was the negative control. Relative to cholestyramine, in vitro bile acid binding on dry matter basis was for the collard greens, kale, and mustard greens, 13%; broccoli, 10%; Brussels sprouts and spinach, 8%; green bell pepper, 7%; and cabbage, 5%. These results point to the significantly different (P < or = .05) health-promoting potential of collard greens = kale = mustard greens > broccoli > Brussels sprouts = spinach = green bell pepper > cabbage as indicated by their bile acid binding on dry matter basis. Steam cooking significantly improved the in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage compared with previously observed bile acid binding values for these vegetables raw (uncooked). Inclusion of steam-cooked collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage in our daily diet as health-promoting vegetables should be emphasized. These green

  15. Bile salts stimulate recruitment of IpaB to the Shigella flexneri surface, where it colocalizes with IpaD at the tip of the type III secretion needle.

    PubMed

    Olive, Andrew J; Kenjale, Roma; Espina, Marianela; Moore, David S; Picking, Wendy L; Picking, William D

    2007-05-01

    Shigella flexneri uses its type III secretion apparatus (TTSA) to deliver invasins into human cells. This TTSA possesses an external needle with IpaD at its tip. We now show that deoxycholate promotes the stable recruitment of IpaB to the needle tip without inducing a rapid burst of type III secretion. The maintenance of IpaB at the needle tip requires a stable association of IpaD with the Shigella surface. This is the first demonstration of a translocator protein being stably associated with the TTSA needle.

  16. Further studies on the ability of different metal salts to influence the DNA synthesis of human lymphoid cells.

    PubMed

    Nordlind, K

    1986-01-01

    In a further study on the ability of different metal salts to influence the DNA synthesis of human lymphoid cells, aluminum chloride, beryllium chloride, cadmium chloride, cupric sulfate, ferric chloride, manganese chloride, palladium chloride, platinum chloride and silver nitrate, were tested regarding effect on thymocytes and peripheral blood lymphocytes in children. At certain concentrations in the range of 10(-4)-10(-5)M, all tested compounds but aluminum chloride and ferric chloride, were inhibitory, the latter compounds inhibited at 4.8 X 10(-3)M. A slight stimulation mainly on the thymocytes was obtained with beryllium chloride, cadmium chloride, palladium chloride, platinum chloride and silver nitrate, at certain concentrations in the range of 10(-5)-10(-6)M, while ferric chloride gave a slight stimulation at 1.2 X 10(-3)M. Thus, the tested metal salts should be suitable for use in lymphocyte transformation tests for diagnosis of contact allergy.

  17. Relative contributions of the fraction of unfrozen water and of salt concentration to the survival of slowly frozen human erythrocytes

    SciTech Connect

    Mazur, P.; Rall, W.F.; Rigopoulos, N.

    1981-12-01

    As suspensions of cells freeze, the electrolytes and other solutes in the external solution concentrate progressively, and the cells undergo osmotic dehydration if cooling is slow. The progressive concentration of solute comes about as increasing amounts of pure ice precipitate out of solution and cause the liquid-filled channels in which the cells are sequestered to dwindle in size. The consensus has been that slow freezing injury is related to the composition of the solution in these channels and not to the amount of residual liquid. The purpose of the research reported here was to test this assumption on human erythrocytes. Two solutes were used here: NaCl and the permeating protective addivitve glycerol. Human red cells were suspended in solutions with weight ratios of glycerol to NaCl of either 6.42 or 11.26, where the concentrations of NaCl were 0.6, 0.75, 1.0, 2.0, 3.0, or 4.0 times isotonic. Samples were then frozen to various subzero temperatures, which were chosen to produce various molalities of NaCl (0.24-3.30) while holding the fraction of unfrozen water constant, or conversely to produce various unfrozen fractions (0.03-0.5) while holding the molality of salt constant. (Not all combinations of these values were possible). The following general findings emerged: (a) few cells survived the freezing of > 90% of the extracellular water regardless of the salt concentration in the residual unfrozen portion, (b) When the fraction of frozen water was < 75%, the majority of the cells survived even when the salt concentration in the unfrozen portion exceeded 2 molal. (c) Salt concentration affected survival significantly only when the frozen fractionlay between 75 and 90%

  18. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic {beta} cells

    SciTech Connect

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila; Mirshahi, Faridoddin; Grider, John R.; Murthy, Karnam S.; Sanyal, Arun J.

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer G protein coupled receptor TGR5 is expressed in mouse and human islets. Black-Right-Pointing-Pointer TGR5 is coupled to activation of Gs and Ca{sup 2+} release via cAMP/Epac/PLC-{epsilon} pathway. Black-Right-Pointing-Pointer Activation of TGR5 by bile salts and selective ligands causes insulin secretion. Black-Right-Pointing-Pointer TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic {beta} cells. In the present study, we have identified the expression of TGR5 in pancreatic {beta} cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated G{alpha}{sub s} and caused an increase in intracellular cAMP and Ca{sup 2+}. OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective G{alpha}{sub s} inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G{sub s}/cAMP/Ca{sup 2+} pathway. 8-pCPT-2 Prime -O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic {beta} cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  19. Quantitative assessment of canalicular bile formation in isolated hepatocyte couplets using microscopic optical planimetry.

    PubMed Central

    Gautam, A; Ng, O C; Strazzabosco, M; Boyer, J L

    1989-01-01

    Isolated rat hepatocyte couplets (IRHC) are primary units of bile secretion that accumulate fluid in an enclosed canalicular space with time in culture. We have quantitated the rate of canalicular secretion in IRHC cultured for 4-8 h by measuring the change in canalicular space volume by video-microscopic optical planimetry using high resolution Nomarski optics. Electron microscopic morphometric studies revealed significant increases in canalicular membrane area after 4-6 h in culture. Canalicular secretion in basal L-15 medium (3.8 +/- 1.3 fl/min) increased significantly with the choleretic bile salts (10 microM), taurocholate, and ursodeoxycholate (14 +/- 7 fl/min each). Secretion rates after exposure to bile acids correlated directly with the canalicular surface area before stimulation. In contrast, expansion times after stimulation varied inversely with initial canalicular volumes. Ursodeoxycholic acid failed to produce a hypercholeresis at 10-, 100-, or 200-microM concentrations compared with taurocholate, either in normal or taurine-depleted IRHC. The present findings establish that rates of canalicular bile secretion can be quantitated in IRHC by serial optical planimetry, both in the basal state and after stimulation with bile acids. Furthermore, ursodeoxycholate does not acutely induce hypercholeresis at the canalicular level in this model. Rather, both taurocholic and ursodeoxycholic acids induced secretion in proportion to the surface area of the canalicular membrane. The IRHC are a useful model to identify canalicular choleretics and for studies of canalicular bile formation. Images PMID:2913052

  20. Effect of bile on nisin-mediated antibacterial activity and the expression of nisin genes of Lactococcus lactis W8.

    PubMed

    Mitra, Suranjita; Mukhopadhyay, Bidhan Chandra; Chakrabartty, Pran Krishna; Biswas, Swadesh Ranjan

    2013-12-01

    The capability of Lactococcus lactis to produce nisin in the presence of bile in the intestinal environment remains an intriguing question. The aim of this study was to determine the effects of bile on production of nisin and the mRNA expression of nisin genes of L. lactis W8. The strain L. lactis W8 was grown on glucose in the absence and presence of bile (0.005-0.08 %) and the antibacterial activities of culture supernatants were determined. In culture with 0.035 % bile, the nisin activity was significantly reduced (400 AU/mL) within 5 h compared to that in the control without bile (2000 AU/mL), while growth of the cells was only slightly affected. In the presence of 0.07 % bile no nisin activity of the strain was manifested. Consistent with these results, mRNA expression of nisin-biosynthetic genes nisZ, nisRK, nisI, and nisF was down-regulated by 7.5-, 2.5-, 1.7-, and 6.0-fold, respectively in cells grown in the presence of bile (0.07 %) as compared to control culture without bile. The present study suggested that bile inhibited transcription of nisin genes. Nisin-production in intestine by orally administered L. lactis, thus, does not occur since complete inhibition of nisin-production by bile is observed at a concentration much lower than the physiological concentration (0.3 %) of bile present in the human intestine. The molecular mechanism underlying the bile-mediated inhibition of nisin genes remains to be elucidated. This is the first report on bile-mediated inhibition of nisin genes.

  1. Structural basis of the alternating-access mechanism in a bile acid transporter

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoming; Levin, Elena J.; Pan, Yaping; McCoy, Jason G.; Sharma, Ruchika; Kloss, Brian; Bruni, Renato; Quick, Matthias; Zhou, Ming

    2014-01-01

    Bile acids are synthesized from cholesterol in hepatocytes and secreted through the biliary tract into the small intestine, where they aid in absorption of lipids and fat-soluble vitamins. Through a process known as enterohepatic recirculation, more than 90% of secreted bile acids are then retrieved from the intestine and returned to the liver for resecretion. In humans, there are two Na+-dependent bile acid transporters involved in enterohepatic recirculation, the Na+-taurocholate co-transporting polypeptide (NTCP; also known as SLC10A1) expressed in hepatocytes, and the apical sodium-dependent bile acid transporter (ASBT; also known as SLC10A2) expressed on enterocytes in the terminal ileum. In recent years, ASBT has attracted much interest as a potential drug target for treatment of hypercholesterolaemia, because inhibition of ASBT reduces reabsorption of bile acids, thus increasing bile acid synthesis and consequently cholesterol consumption. However, a lack of three-dimensional structures of bile acid transporters hampers our ability to understand the molecular mechanisms of substrate selectivity and transport, and to interpret the wealth of existing functional data. The crystal structure of an ASBT homologue from Neisseria meningitidis (ASBTNM) in detergent was reported recently, showing the protein in an inward-open conformation bound to two Na+ and a taurocholic acid. However, the structural changes that bring bile acid and Na+ across the membrane are difficult to infer from a single structure. To understand the structural changes associated with the coupled transport of Na+ and bile acids, here we solved two structures of an ASBT homologue from Yersinia frederiksenii (ASBTYf) in a lipid environment, which reveal that a large rigid-body rotation of a substrate-binding domain gives the conserved `crossover' region, where two discontinuous helices cross each other, alternating accessibility from either side of the cell membrane. This result has implications

  2. Bile acids of snakes of the subfamily Viperinae and the biosynthesis of C-23-hydroxylated bile acids in liver homogenate fractions from the adder, Vipera berus (Linn.).

    PubMed Central

    Ikawa, S; Tammar, A R

    1976-01-01

    1. Analysis of bile salts of four snakes of the subfamily Viperinae showed that their bile acids consisted mainly of C-23-hydroxylated bile acids. 2. Incubations of 14C-labelled sodium cholate (3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholan-24-oate) and deoxycholate (3 alpha, 12 alpha-dihydroxy-5 beta-cholan-24-oate) with whole and fractionated adder liver homogenates were carried out in the presence of molecular oxygen and NADPH or an NADPH-generating system. The formation of C-23-hydroxylated bile acids, namely bitocholic acid (3 alpha, 12 alpha, 23xi-trihydroxy-5 beta-cholan-24-oic acid) and 3 alpha, 7 alpha, 12 alpha, 23 xi-tetrahydroxy-cholanic acid (3 alpha, 7 alpha, 12 alpha, 23 xi-tetrahydroxy-5 beta-cholan-24-oic acid), was observed mainly in the microsomal fraction and partly in the mitochondrial fraction. 3. Biosynthetic pathways of C-23-hydroxylated bile acids are discussed. PMID:6007

  3. Effect of bile diversion on satiety and fat absorption from liquid and solid dietary sources

    SciTech Connect

    Doty, J.E.; Gu, Y.G.; Meyer, J.H.

    1988-12-01

    In previous studies, liquid fat has been used to determine the effect of bile diversion on fat absorption. Since protein digests, in addition to bile salts, are capable of solubilizing lipids, we hypothesized that fat incorporated in the protein-rich matrix of solid food would be less sensitive to bile diversion than fat ingested as an oil or liquid. Using (3H)glycerol triether as a nonabsorbable fat recovery marker, we determined how much (14C)triolein was absorbed from solid (chicken liver) and liquid (margarine) dietary sources. After a standard liquid/solid meal with either the chicken liver or margarine labeled, midintestinal chyme was collected for 6 hr, extracted, and counted for 14C and 3H activity. Zero, eighty, or one hundred percent of endogenous bile was diverted. Fat absorption from both chicken liver and margarine was nearly complete by midintestine with 0% diversion and was little affected by diversion of 80% of bile. Complete biliary diversion significantly decreased fat absorption from margarine (87.9 +/- 4.4 to 37.2 +/- 9.2%, P less than 0.05) but reduced (14C)triolein absorption from chicken liver less consistently and insignificantly (78.8 +/- 6.9 to 43.9 +/- 10.6%). These data indicate that fat absorption is not solely dependent on bile and support the hypothesis that fat ingested in a cellular matrix is less dependent on bile than liquid fat. Using these same animals but with the midintestinal cannulas plugged to expose the distal intestine to unabsorbed luminal nutrients, we also demonstrated that bile diversion of an initial meal reduced food consumption at a meal offered 3 hr later.

  4. The rule of unity for human intestinal absorption 2: application to pharmaceutical drugs that are marketed as salts.

    PubMed

    Patel, Raj B; Admire, Brittany; Yalkowsky, Samuel H

    2015-01-01

    The efficiency of the human intestinal absorption (HIA) of the 59 drugs which are marketed as salts is predicted using the rule of unity. Intrinsic aqueous solubilities and partition coefficients along with the drug dose are used to calculate modified absorption potential (MAP) values. These values are shown to be related to the fraction of the dose that is absorbed upon oral administration in humans (FA). It is shown that the MAP value can distinguish between drugs that are poorly absorbed (FA <0.5) and those that are well absorbed (FA ≥ 0.5). Inspection of the data as well as a receiver operative characteristic (ROC) plot shows that a single critical MAP value can be used for predicting efficient human absorption of drugs. This forms the basis of a simple rule of unity based solely on in vitro data for predicting whether or not a drug will be well absorbed at a given dose.

  5. Solvent isotope effect on bile formation in the rat.

    PubMed Central

    Elsing, C; Hirlinger, A; Renner, E L; Lauterburg, B H; Meier, P J; Reichen, J

    1995-01-01

    2H2O affects many membrane transport processes by solvent and kinetic isotope effects. Since bile formation is a process of osmotic filtration where such effects could be important, we investigated the effects of 2H2O on bile formation in the in situ perfused rat liver. Dose finding experiments showed that at high concentrations, 2H2O increased vascular resistance and induced cholestasis; at 60% 2H2O however, a clear dissociation between the vascular and biliary effects was observed. Therefore, further experiments were carried out at this concentration. The main finding was a reduction in bile salt-independent bile flow from 0.99 +/- 0.04 to 0.66 +/- 0.04 microliters.min-1.g-1 (P < 0.001). This was associated with a 40% reduction in biliary bicarbonate concentration (P < 0.001). Choleretic response to neither taurocholate nor ursodeoxycholate was altered by 2H2O; in particular, there was a similar stimulation of bicarbonate secretion by ursodeoxycholate in the presence of 60% 2H2O. To further elucidate this phenomenon, the effect of 2H2O on three proteins potentially involved in biliary bicarbonate secretion was studied in vitro. 2H2O slightly inhibited cytosolic carboanhydrase and leukocyte Na+/H(+)-exchange, these effects reached statistical significance at 100% 2H2O only, however. In contrast, Cl-/HCO(3-)-exchange in canalicular membrane vesicles was already inhibited by 50% (P < 0.001) at 60% 2H2O. Finally, there was a slight reduction in biliary glutathione secretion while that of the disulphide was not affected. Our results are compatible with an inhibition of canalicular Cl-/HCO(3-)-exchange by 2H2O. Whether this is due to altered hydration of the exchanger and/or of the transported bicarbonate remains to be determined. PMID:7717973

  6. Solvent isotope effect on bile formation in the rat.

    PubMed

    Elsing, C; Hirlinger, A; Renner, E L; Lauterburg, B H; Meier, P J; Reichen, J

    1995-04-01

    2H2O affects many membrane transport processes by solvent and kinetic isotope effects. Since bile formation is a process of osmotic filtration where such effects could be important, we investigated the effects of 2H2O on bile formation in the in situ perfused rat liver. Dose finding experiments showed that at high concentrations, 2H2O increased vascular resistance and induced cholestasis; at 60% 2H2O however, a clear dissociation between the vascular and biliary effects was observed. Therefore, further experiments were carried out at this concentration. The main finding was a reduction in bile salt-independent bile flow from 0.99 +/- 0.04 to 0.66 +/- 0.04 microliters.min-1.g-1 (P < 0.001). This was associated with a 40% reduction in biliary bicarbonate concentration (P < 0.001). Choleretic response to neither taurocholate nor ursodeoxycholate was altered by 2H2O; in particular, there was a similar stimulation of bicarbonate secretion by ursodeoxycholate in the presence of 60% 2H2O. To further elucidate this phenomenon, the effect of 2H2O on three proteins potentially involved in biliary bicarbonate secretion was studied in vitro. 2H2O slightly inhibited cytosolic carboanhydrase and leukocyte Na+/H(+)-exchange, these effects reached statistical significance at 100% 2H2O only, however. In contrast, Cl-/HCO(3-)-exchange in canalicular membrane vesicles was already inhibited by 50% (P < 0.001) at 60% 2H2O. Finally, there was a slight reduction in biliary glutathione secretion while that of the disulphide was not affected. Our results are compatible with an inhibition of canalicular Cl-/HCO(3-)-exchange by 2H2O. Whether this is due to altered hydration of the exchanger and/or of the transported bicarbonate remains to be determined. PMID:7717973

  7. Staphylococcus aureus MnhF Mediates Cholate Efflux and Facilitates Survival under Human Colonic Conditions

    PubMed Central

    Sannasiddappa, Thippeswamy H.; Hood, Graham A.; Hanson, Kevan J.; Costabile, Adele; Gibson, Glenn R.

    2015-01-01

    Resistance to the innate defenses of the intestine is crucial for the survival and carriage of Staphylococcus aureus, a common colonizer of the human gut. Bile salts produced by the liver and secreted into the intestines are one such group of molecules with potent antimicrobial activity. The mechanisms by which S. aureus is able to resist such defenses in order to colonize and survive in the human gut are unknown. Here we show that mnhF confers resistance to bile salts, which can be abrogated by efflux pump inhibitors. MnhF mediates the efflux of radiolabeled cholic acid both in S. aureus and when heterologously expressed in Escherichia coli, rendering them resistant. Deletion of mnhF attenuated the survival of S. aureus in an anaerobic three-stage continuous-culture model of the human colon (gut model), which represents different anatomical areas of the large intestine. PMID:25824834

  8. Intestinal transport and metabolism of bile acids

    PubMed Central

    Dawson, Paul A.; Karpen, Saul J.

    2015-01-01

    In addition to their classical roles as detergents to aid in the process of digestion, bile acids have been identified as important signaling molecules that function through various nuclear and G protein-coupled receptors to regulate a myriad of cellular and molecular functions across both metabolic and nonmetabolic pathways. Signaling via these pathways will vary depending on the tissue and the concentration and chemical structure of the bile acid species. Important determinants of the size and composition of the bile acid pool are their efficient enterohepatic recirculation, their host and microbial metabolism, and the homeostatic feedback mechanisms connecting hepatocytes, enterocytes, and the luminal microbiota. This review focuses on the mammalian intestine, discussing the physiology of bile acid transport, the metabolism of bile acids in the gut, and new developments in our understanding of how intestinal metabolism, particularly by the gut microbiota, affects bile acid signaling. PMID:25210150

  9. [Bile leakage in laparoscopic cholecystectomy. Authors' experience].

    PubMed

    Sperlongano, P; Pisaniello, D; Corsale, I; Cozza, G

    1999-01-01

    The Authors report their experience of two patients with bile leakage following videocholecystectomy (VLC) among a series of 163 cases. Reviewing the Literature, they analyze possible causes and mechanisms of bile spillage occurring after VCL. They also suggest some guidelines for a safe VLC, stressing the importance of the routinary placement of the sub-hepatic drainage to remove 48 hours to early detect possible bile leakages after surgery.

  10. Serum bile acids in patients with hyperlipidaemia.

    PubMed Central

    Pennington, C R; Ross, P E; Bateson, M C; Bouchier, I A

    1978-01-01

    Individual serum bile acids were analysed by an improved gas liquid chromatography method in 12 patients with primary hyperlipidaemia. Total serum bile acid concentrations were raised in 10 subjects. Ursodeoxycholic acid was found in all 12 patients. It was present in significantly greater concentrations, accounted for a greater proportion of the total serum bile acids, and occurred more frequently than in patients with various forms of hepatobiliary disease. Patients with hyperlipidaemia had proportionately less deoxycholic acid than controls but more than patients with liver disease. There was proportionately less chenodeoxycholic acid in patients with hypercholesterolaemia, in whom the primary bile acid ratio was raised. PMID:627619

  11. History and future of human cadaver preservation for surgical training: from formalin to saturated salt solution method.

    PubMed

    Hayashi, Shogo; Naito, Munekazu; Kawata, Shinichi; Qu, Ning; Hatayama, Naoyuki; Hirai, Shuichi; Itoh, Masahiro

    2016-01-01

    Traditionally, surgical training meant on-the-job training with live patients in an operating room. However, due to advancing surgical techniques, such as minimally invasive surgery, and increasing safety demands during procedures, human cadavers have been used for surgical training. When considering the use of human cadavers for surgical training, one of the most important factors is their preservation. In this review, we summarize four preservation methods: fresh-frozen cadaver, formalin, Thiel's, and saturated salt solution methods. Fresh-frozen cadaver is currently the model that is closest to reality, but it also presents myriad problems, including the requirement of freezers for storage, limited work time because of rapid putrefaction, and risk of infection. Formalin is still used ubiquitously due to its low cost and wide availability, but it is not ideal because formaldehyde has an adverse health effect and formalin-embalmed cadavers do not exhibit many of the qualities of living organs. Thiel's method results in soft and flexible cadavers with almost natural colors, and Thiel-embalmed cadavers have been appraised widely in various medical disciplines. However, Thiel's method is relatively expensive and technically complicated. In addition, Thiel-embalmed cadavers have a limited dissection time. The saturated salt solution method is simple, carries a low risk of infection, and is relatively low cost. Although more research is needed, this method seems to be sufficiently useful for surgical training and has noteworthy features that expand the capability of clinical training. The saturated salt solution method will contribute to a wider use of cadavers for surgical training.

  12. The role of bile carcinoembryonic antigen in diagnosing bile duct cancer.

    PubMed Central

    Joo, Kwang Ro; Kim, Do Ha; Park, Jong Ho; Bang, Sung-Jo; Shin, Jung Woo; Park, Neung Hwa; Park, Jae Hoo

    2003-01-01

    It is known that the fluids bathing tumors might contain a higher level of the carcinoembryonic antigen (CEA) than those found in the blood. Therefore, we evaluated the role of bile CEA in diagnosing bile duct cancer. One hundred and thirty two patients were prospectively studied. The patients were divided into 3 groups: the bile duct cancer (n=32), pancreatic cancer (n=16), and benign biliary diseases (n=84) groups. Bile samples were obtained on the next day of the biliary drainage procedures. The mean bile CEA level in those with bile duct cancer (120.6 +/- 156.9 ng/mL) was significantly higher than those with pancreatic cancer and benign biliary diseases (32.0 +/- 28.5 ng/mL, 29.3 +/- 56.3 ng/mL). Using the level of 20 ng/mL, the sensitivity and specificity of bile CEA in the diagnosis of bile duct cancer from benign biliary diseases were 65.6% and 66.7%, respectively. Both the bile CEA and total bilirubin level were found to be an independent factor linked to bile duct cancer. This study result suggests that bile CEA level is a useful supplementary test for diagnosing bile duct cancer. PMID:14676443

  13. Regulation of host weight gain and lipid metabolism by bacterial bile acid modification in the gut.

    PubMed

    Joyce, Susan A; MacSharry, John; Casey, Patrick G; Kinsella, Michael; Murphy, Eileen F; Shanahan, Fergus; Hill, Colin; Gahan, Cormac G M

    2014-05-20

    Alterations in the gastrointestinal microbiota have been implicated in obesity in mice and humans, but the key microbial functions influencing host energy metabolism and adiposity remain to be determined. Despite an increased understanding of the genetic content of the gastrointestinal microbiome, functional analyses of common microbial gene sets are required. We established a controlled expression system for the parallel functional analysis of microbial alleles in the murine gut. Using this approach we show that bacterial bile salt hydrolase (BSH) mediates a microbe-host dialogue that functionally regulates host lipid metabolism and plays a profound role in cholesterol metabolism and weight gain in the host. Expression of cloned BSH enzymes in the gastrointestinal tract of gnotobiotic or conventionally raised mice significantly altered plasma bile acid signatures and regulated transcription of key genes involved in lipid metabolism (Pparγ, Angptl4), cholesterol metabolism (Abcg5/8), gastrointestinal homeostasis (RegIIIγ), and circadian rhythm (Dbp, Per1/2) in the liver or small intestine. High-level expression of BSH in conventionally raised mice resulted in a significant reduction in host weight gain, plasma cholesterol, and liver triglycerides, demonstrating the overall impact of elevated BSH activity on host physiology. In addition, BSH activity in vivo varied according to BSH allele group, indicating that subtle differences in activity can have significant effects on the host. In summary, we demonstrate that bacterial BSH activity significantly impacts the systemic metabolic processes and adiposity in the host and represents a key mechanistic target for the control of obesity and hypercholesterolemia. PMID:24799697

  14. Intestinal GPS: bile and bicarbonate control cyclic di-GMP to provide Vibrio cholerae spatial cues within the small intestine

    PubMed Central

    Koestler, Benjamin J; Waters, Christopher M

    2014-01-01

    The second messenger cyclic di-GMP (c-di-GMP) regulates numerous phenotypes in response to environmental stimuli to enable bacteria to transition between different lifestyles. Here we discuss our recent findings that the human pathogen Vibrio cholerae recognizes 2 host-specific signals, bile and bicarbonate, to regulate intracellular c-di-GMP. We have demonstrated that bile acids increase intracellular c-di-GMP to promote biofilm formation. We have also shown that this bile-mediated increase of intracellular c-di-GMP is negated by bicarbonate, and that this interaction is dependent on pH, suggesting that V. cholerae uses these 2 environmental cues to sense and adapt to its relative location in the small intestine. Increased intracellular c-di-GMP by bile is attributed to increased c-di-GMP synthesis by 3 diguanylate cyclases (DGCs) and decreased expression of one phosphodiesterase (PDE) in the presence of bile. The molecular mechanisms by which bile controls the activity of the 3 DGCs and the regulators of bile-mediated transcriptional repression of the PDE are not yet known. Moreover, the impact of varying concentrations of bile and bicarbonate at different locations within the small intestine and the response of V. cholerae to these cues remains unclear. The native microbiome and pharmaceuticals, such as omeprazole, can impact bile and pH within the small intestine, suggesting these are potential unappreciated factors that may alter V. cholerae pathogenesis. PMID:25621620

  15. Intestinal GPS: bile and bicarbonate control cyclic di-GMP to provide Vibrio cholerae spatial cues within the small intestine.

    PubMed

    Koestler, Benjamin J; Waters, Christopher M

    2014-01-01

    The second messenger cyclic di-GMP (c-di-GMP) regulates numerous phenotypes in response to environmental stimuli to enable bacteria to transition between different lifestyles. Here we discuss our recent findings that the human pathogen Vibrio cholerae recognizes 2 host-specific signals, bile and bicarbonate, to regulate intracellular c-di-GMP. We have demonstrated that bile acids increase intracellular c-di-GMP to promote biofilm formation. We have also shown that this bile-mediated increase of intracellular c-di-GMP is negated by bicarbonate, and that this interaction is dependent on pH, suggesting that V. cholerae uses these 2 environmental cues to sense and adapt to its relative location in the small intestine. Increased intracellular c-di-GMP by bile is attributed to increased c-di-GMP synthesis by 3 diguanylate cyclases (DGCs) and decreased expression of one phosphodiesterase (PDE) in the presence of bile. The molecular mechanisms by which bile controls the activity of the 3 DGCs and the regulators of bile-mediated transcriptional repression of the PDE are not yet known. Moreover, the impact of varying concentrations of bile and bicarbonate at different locations within the small intestine and the response of V. cholerae to these cues remains unclear. The native microbiome and pharmaceuticals, such as omeprazole, can impact bile and pH within the small intestine, suggesting these are potential unappreciated factors that may alter V. cholerae pathogenesis. PMID:25621620

  16. Evaluation of Streptococcus pneumoniae in bile samples: A case series review.

    PubMed

    Itoh, Naoya; Kawamura, Ichiro; Tsukahara, Mika; Mori, Keita; Kurai, Hanako

    2016-06-01

    Although Streptococcus pneumoniae is an important pathogen of humans, pneumococcal cholangitis is rare because of the rapid autolysis of S. pneumoniae. The aim of this case series was to review patients with bile cultures positive for S. pneumoniae. This study was a single center retrospective case series review of patients with S. pneumoniae in their bile at a tertiary-care cancer center between September 2002 and August 2015. Subjects consisted of all patients in whom S. pneumoniae was isolated in their bile during the study period. Bile specimens for culture were obtained from biliary drainage procedures such as endoscopic retrograde biliary drainage, endoscopic nasobiliary drainage, and percutaneous transhepatic biliary drainage. There were 20 patients with bile cultures positive for S. pneumoniae during the study period. All patients presented with extrahepatic obstructive jaundice due to hepatopancreatobiliary tumors. Nineteen of 20 patients underwent the placement of plastic intrabiliary tubes. The mean time between the first-time drainage and the positive culture was 26 days (range 0-313 days). Although 12 of 20 patients met our definition of cholangitis, 5 were clinically treated with antibiotics based on a physician's assessment of whether there was a true infection. The present study is the largest case series of patients with S. pneumoniae in their bile. Based on our findings, the isolation of S. pneumoniae from bile may be attributed to the placement of biliary drainage devices. PMID:27025902

  17. The Gut Microbiota as a Therapeutic Target in IBD and Metabolic Disease: A Role for the Bile Acid Receptors FXR and TGR5

    PubMed Central

    Baars, Annemarie; Oosting, Annemarie; Knol, Jan; Garssen, Johan; van Bergenhenegouwen, Jeroen

    2015-01-01

    The gut microbiota plays a crucial role in regulating many physiological systems of the host, including the metabolic and immune system. Disturbances in microbiota composition are increasingly correlated with disease; however, the underlying mechanisms are not well understood. Recent evidence suggests that changes in microbiota composition directly affect the metabolism of bile salts. Next to their role in digestion of dietary fats, bile salts function as signaling molecules for bile salt receptors such as Farnesoid X receptor (FXR) and G protein-coupled bile acid receptor (TGR5). Complementary to their role in metabolism, FXR and TGR5 are shown to play a role in intestinal homeostasis and immune regulation. This review presents an overview of evidence showing that changes in bile salt pool and composition due to changes in gut microbial composition contribute to the pathogenesis of inflammatory bowel disease and metabolic disease, possibly through altered activation of TGR5 and FXR. We further discuss how dietary interventions, such as pro- and synbiotics, may be used to treat metabolic disease and inflammatory bowel disease (IBD) through normalization of bile acid dysregulation directly or indirectly through normalization of the intestinal microbiota.

  18. The Gut Microbiota as a Therapeutic Target in IBD and Metabolic Disease: A Role for the Bile Acid Receptors FXR and TGR5

    PubMed Central

    Baars, Annemarie; Oosting, Annemarie; Knol, Jan; Garssen, Johan; van Bergenhenegouwen, Jeroen

    2015-01-01

    The gut microbiota plays a crucial role in regulating many physiological systems of the host, including the metabolic and immune system. Disturbances in microbiota composition are increasingly correlated with disease; however, the underlying mechanisms are not well understood. Recent evidence suggests that changes in microbiota composition directly affect the metabolism of bile salts. Next to their role in digestion of dietary fats, bile salts function as signaling molecules for bile salt receptors such as Farnesoid X receptor (FXR) and G protein-coupled bile acid receptor (TGR5). Complementary to their role in metabolism, FXR and TGR5 are shown to play a role in intestinal homeostasis and immune regulation. This review presents an overview of evidence showing that changes in bile salt pool and composition due to changes in gut microbial composition contribute to the pathogenesis of inflammatory bowel disease and metabolic disease, possibly through altered activation of TGR5 and FXR. We further discuss how dietary interventions, such as pro- and synbiotics, may be used to treat metabolic disease and inflammatory bowel disease (IBD) through normalization of bile acid dysregulation directly or indirectly through normalization of the intestinal microbiota. PMID:27682110

  19. Genetics Home Reference: congenital bile acid synthesis defect type 1

    MedlinePlus

    ... bile acid synthesis defect type 1 congenital bile acid synthesis defect type 1 Enable Javascript to view ... PDF Open All Close All Description Congenital bile acid synthesis defect type 1 is a disorder characterized ...

  20. Genetics Home Reference: congenital bile acid synthesis defect type 2

    MedlinePlus

    ... bile acid synthesis defect type 2 congenital bile acid synthesis defect type 2 Enable Javascript to view ... PDF Open All Close All Description Congenital bile acid synthesis defect type 2 is a disorder characterized ...

  1. Thermosensitivity of bile acid-based oligo(ethylene glycol) stars in aqueous solutions.

    PubMed

    Strandman, Satu; Le Dévédec, Frantz; Zhu, X X

    2011-08-01

    Amphiphilic star-shaped oligo(ethylene glycol)s with a hydrophobic bile acid core and varying number of hydrophilic arms have been made. Their thermal behavior in aqueous solutions depends on the number rather than the length of the arms. The two-armed lithocholate derivative showed the strongest tendency for association and exhibited the lowest cloud point (79 °C) of the oligomers made, as well as another phase separation at a lower temperature (31 °C). The "double thermosensitivity" arising both from the salt-dependent LCST of the oligo(ethylene glycol) segments and the temperature-responsive self-assembly of amphiphilic bile acid derivative provides an interesting path in the design of bile acid-based smart materials.

  2. Thermosensitivity of bile acid-based oligo(ethylene glycol) stars in aqueous solutions.

    PubMed

    Strandman, Satu; Le Dévédec, Frantz; Zhu, X X

    2011-08-01

    Amphiphilic star-shaped oligo(ethylene glycol)s with a hydrophobic bile acid core and varying number of hydrophilic arms have been made. Their thermal behavior in aqueous solutions depends on the number rather than the length of the arms. The two-armed lithocholate derivative showed the strongest tendency for association and exhibited the lowest cloud point (79 °C) of the oligomers made, as well as another phase separation at a lower temperature (31 °C). The "double thermosensitivity" arising both from the salt-dependent LCST of the oligo(ethylene glycol) segments and the temperature-responsive self-assembly of amphiphilic bile acid derivative provides an interesting path in the design of bile acid-based smart materials. PMID:21661073

  3. Synthesis, characterization and biological activity of hydroxyl-bisphosphonic analogs of bile acids.

    PubMed

    Bortolini, Olga; Fantin, Giancarlo; Fogagnolo, Marco; Rossetti, Stefano; Maiuolo, Loredana; Di Pompo, Gemma; Avnet, Sofia; Granchi, Donatella

    2012-06-01

    Bisphosphonates (BPs) are now the most widely used drugs for diseases associated with increased bone resorption, such as osteoporosis, and tumor bone diseases. A significant drawback of the BPs is their poor oral absorption that is enhanced by the presence of bile acid substituents in the bisphosphonate framework, with no toxic effects. A straightforward synthesis of bile acid-containing hydroxy-bisphosphonates and a full characterization of these pharmaceutically important molecules, including an evaluation of affinity and the mechanism of binding to hydroxyapatite, is presented. The biological activity of bile acid-containing bisphosphonate salts was determined using the neutral-red assay on the L929 cell line and primary cultures of osteoclasts. The bioactivity of the new compounds was found superior than bisphosphonates of established activity. PMID:22483634

  4. Multitask Imidazolium Salt Additives for Innovative Poly(l-lactide) Biomaterials: Morphology Control, Candida spp. Biofilm Inhibition, Human Mesenchymal Stem Cell Biocompatibility, and Skin Tolerance.

    PubMed

    Schrekker, Clarissa M L; Sokolovicz, Yuri C A; Raucci, Maria G; Selukar, Balaji S; Klitzke, Joice S; Lopes, William; Leal, Claudio A M; de Souza, Igor O P; Galland, Griselda B; Dos Santos, João Henrique Z; Mauler, Raquel S; Kol, Moshe; Dagorne, Samuel; Ambrosio, Luigi; Teixeira, Mário L; Morais, Jonder; Landers, Richard; Fuentefria, Alexandre M; Schrekker, Henri S

    2016-08-24

    Candida species have great ability to colonize and form biofilms on medical devices, causing infections in human hosts. In this study, poly(l-lactide) films with different imidazolium salt (1-n-hexadecyl-3-methylimidazolium chloride (C16MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16MImMeS)) contents were prepared, using the solvent casting process. Poly(l-lactide)-imidazolium salt films were obtained with different surface morphologies (spherical and directional), and the presence of the imidazolium salt in the surface was confirmed. These films with different concentrations of the imidazolium salts C16MImCl and C16MImMeS presented antibiofilm activity against isolates of Candida tropicalis, Candida parapsilosis, and Candida albicans. The minor antibiofilm concentration assay enabled one to determine that an increasing imidazolium salt content promoted, in general, an increase in the inhibition percentage of biofilm formation. Scanning electron microscopy micrographs confirmed the effective prevention of biofilm formation on the imidazolium salt containing biomaterials. Lower concentrations of the imidazolium salts showed no cytotoxicity, and the poly(l-lactide)-imidazolium salt films presented good cell adhesion and proliferation percentages with human mesenchymal stem cells. Furthermore, no acute microscopic lesions were identified in the histopathological evaluation after contact between the films and pig ear skin. In combination with the good morphological, physicochemical, and mechanical properties, these poly(l-lactide)-based materials with imidazolium salt additives can be considered as promising biomaterials for use in the manufacturing of medical devices. PMID:27486827

  5. NMR studies reveal the role of biomembranes in modulating ligand binding and release by intracellular bile acid binding proteins.

    PubMed

    Pedò, Massimo; Löhr, Frank; D'Onofrio, Mariapina; Assfalg, Michael; Dötsch, Volker; Molinari, Henriette

    2009-12-18

    Bile acid molecules are transferred vectorially between basolateral and apical membranes of hepatocytes and enterocytes in the context of the enterohepatic circulation, a process regulating whole body lipid homeostasis. This work addresses the role of the cytosolic lipid binding proteins in the intracellular transfer of bile acids between different membrane compartments. We present nuclear magnetic resonance (NMR) data describing the ternary system composed of the bile acid binding protein, bile acids, and membrane mimetic systems, such as anionic liposomes. This work provides evidence that the investigated liver bile acid binding protein undergoes association with the anionic membrane and binding-induced partial unfolding. The addition of the physiological ligand to the protein-liposome mixture is capable of modulating this interaction, shifting the equilibrium towards the free folded holo protein. An ensemble of NMR titration experiments, based on nitrogen-15 protein and ligand observation, confirm that the membrane and the ligand establish competing binding equilibria, modulating the cytoplasmic permeability of bile acids. These results support a mechanism of ligand binding and release controlled by the onset of a bile salt concentration gradient within the polarized cell. The location of a specific protein region interacting with liposomes is highlighted. PMID:19836400

  6. NMR studies reveal the role of biomembranes in modulating ligand binding and release by intracellular bile acid binding proteins.

    PubMed

    Pedò, Massimo; Löhr, Frank; D'Onofrio, Mariapina; Assfalg, Michael; Dötsch, Volker; Molinari, Henriette

    2009-12-18

    Bile acid molecules are transferred vectorially between basolateral and apical membranes of hepatocytes and enterocytes in the context of the enterohepatic circulation, a process regulating whole body lipid homeostasis. This work addresses the role of the cytosolic lipid binding proteins in the intracellular transfer of bile acids between different membrane compartments. We present nuclear magnetic resonance (NMR) data describing the ternary system composed of the bile acid binding protein, bile acids, and membrane mimetic systems, such as anionic liposomes. This work provides evidence that the investigated liver bile acid binding protein undergoes association with the anionic membrane and binding-induced partial unfolding. The addition of the physiological ligand to the protein-liposome mixture is capable of modulating this interaction, shifting the equilibrium towards the free folded holo protein. An ensemble of NMR titration experiments, based on nitrogen-15 protein and ligand observation, confirm that the membrane and the ligand establish competing binding equilibria, modulating the cytoplasmic permeability of bile acids. These results support a mechanism of ligand binding and release controlled by the onset of a bile salt concentration gradient within the polarized cell. The location of a specific protein region interacting with liposomes is highlighted.

  7. Individual bile acids have differential effects on bile acid signaling in mice

    SciTech Connect

    Song, Peizhen Rockwell, Cheryl E. Cui, Julia Yue Klaassen, Curtis D.

    2015-02-15

    pharmacological concentrations of BAs. - Highlights: • All four major bile acids in humans activate the FXR in liver and intestine. • These bile acids decreased the mRNA of the bile acid synthetic enzymes Cyp7a1 and Cyp8b1. • These BAs did not alter the mRNA or protein of the conjugated BA transporters (Ntcp and Bsep). • Cholic acid and deoxycholic acid are more potent activators of FXR than chenodeoxycholic acid and lithocholic acid.

  8. Physiological and molecular biochemical mechanisms of bile formation

    PubMed Central

    Reshetnyak, Vasiliy Ivanovich

    2013-01-01

    This review considers the physiological and molecular biochemical mechanisms of bile formation. The composition of bile and structure of a bile canaliculus, biosynthesis and conjugation of bile acids, bile phospholipids, formation of bile micellar structures, and enterohepatic circulation of bile acids are described. In general, the review focuses on the molecular physiology of the transporting systems of the hepatocyte sinusoidal and apical membranes. Knowledge of physiological and biochemical basis of bile formation has implications for understanding the mechanisms of development of pathological processes, associated with diseases of the liver and biliary tract. PMID:24259965

  9. Circadian dysregulation disrupts bile acid homeostasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acids are potentially toxic compounds and their levels of hepatic production, uptake, and export are tightly regulated by many inputs, including circadian rhythm. We tested the impact of disrupting the peripheral circadian clock on integral steps of bile acid homeostasis. Both restricted feedi...

  10. Species differences in hepatobiliary disposition of taurocholic acid in human and rat sandwich-cultured hepatocytes: implications for drug-induced liver injury.

    PubMed

    Yang, Kyunghee; Pfeifer, Nathan D; Köck, Kathleen; Brouwer, Kim L R

    2015-05-01

    The bile salt export pump (BSEP) plays an important role in bile acid excretion. Impaired BSEP function may result in liver injury. Bile acids also undergo basolateral efflux, but the relative contributions of biliary (CLBile) versus basolateral efflux (CLBL) clearance to hepatocellular bile acid excretion have not been determined. In the present study, taurocholic acid (TCA; a model bile acid) disposition was characterized in human and rat sandwich-cultured hepatocytes (SCH) combined with pharmacokinetic modeling. In human SCH, biliary excretion of TCA predominated (CLBile = 0.14 ± 0.04 ml/min per g liver; CLBL = 0.042 ± 0.019 ml/min per g liver), whereas CLBile and CLBL contributed approximately equally to TCA hepatocellular excretion in rat SCH (CLBile = 0.34 ± 0.07 ml/min per g liver; CLBL = 0.26 ± 0.07 ml/min per g liver). Troglitazone decreased TCA uptake, CLBile, and CLBL; membrane vesicle assays revealed for the first time that the major metabolite, troglitazone sulfate, was a noncompetitive inhibitor of multidrug resistance-associated protein 4, a basolateral bile acid efflux transporter. Simulations revealed that decreased CLBile led to a greater increase in hepatic TCA exposure in human than in rat SCH. A decrease in both excretory pathways (CLBile and CLBL) exponentially increased hepatic TCA in both species, suggesting that 1) drugs that inhibit both pathways may have a greater risk for hepatotoxicity, and 2) impaired function of an alternate excretory pathway may predispose patients to hepatotoxicity when drugs that inhibit one pathway are administered. Simulations confirmed the protective role of uptake inhibition, suggesting that a drug's inhibitory effects on bile acid uptake also should be considered when evaluating hepatotoxic potential. Overall, the current study precisely characterized basolateral efflux of TCA, revealed species differences in hepatocellular TCA efflux pathways, and provided insights about altered hepatic bile acid exposure

  11. Towards the elucidation of molecular determinants of cooperativity in the liver bile acid binding protein.

    PubMed

    Pedò, Massimo; D'Onofrio, Mariapina; Ferranti, Pasquale; Molinari, Henriette; Assfalg, Michael

    2009-11-15

    Bile acid binding proteins (BABPs) are cytosolic lipid chaperones contributing to the maintenance of bile acid homeostasis and functional distribution within the cell. Liver BABPs act in parallel with ileal transporters to ensure vectorial transport of bile salts in hepatocytes and enterocytes, respectively. We describe the investigation of ligand binding to liver BABP, an essential step in the understanding of intracellular bile salt transport. Binding site occupancies were monitored in NMR titration experiments using (15)N-labelled ligand, while the relative populations of differently bound BABP forms were assessed by mass spectrometry. This site-specific information allowed the determination of intrinsic thermodynamic parameters and the identification of an extremely high cooperativity between two binding sites. Protein-observed NMR experiments revealed a global structural rearrangement which suggests an allosteric mechanism at the basis of the observed cooperativity. The view of a molecular tool capable of buffering against significant concentrations of free bile salts in a large range of solution conditions emerges from the observed pH-dependence of binding. We set to determine the molecular determinants of cooperativity by analysing the binding properties of a protein containing a mutated internal histidine. Both mass spectrometry and NMR experiments are consistent with an overall decreased binding affinity of the mutant, while the measured diffusion coefficients of ligand species reveal that the affinity loss concerns essentially one of the two binding sites. We therefore identified a mutation able to disrupt energetic communication functional to efficient binding and conclude that the buried histidine establishes contacts that stabilize the ternary complex. PMID:19603488

  12. Towards the elucidation of molecular determinants of cooperativity in the liver bile acid binding protein.

    PubMed

    Pedò, Massimo; D'Onofrio, Mariapina; Ferranti, Pasquale; Molinari, Henriette; Assfalg, Michael

    2009-11-15

    Bile acid binding proteins (BABPs) are cytosolic lipid chaperones contributing to the maintenance of bile acid homeostasis and functional distribution within the cell. Liver BABPs act in parallel with ileal transporters to ensure vectorial transport of bile salts in hepatocytes and enterocytes, respectively. We describe the investigation of ligand binding to liver BABP, an essential step in the understanding of intracellular bile salt transport. Binding site occupancies were monitored in NMR titration experiments using (15)N-labelled ligand, while the relative populations of differently bound BABP forms were assessed by mass spectrometry. This site-specific information allowed the determination of intrinsic thermodynamic parameters and the identification of an extremely high cooperativity between two binding sites. Protein-observed NMR experiments revealed a global structural rearrangement which suggests an allosteric mechanism at the basis of the observed cooperativity. The view of a molecular tool capable of buffering against significant concentrations of free bile salts in a large range of solution conditions emerges from the observed pH-dependence of binding. We set to determine the molecular determinants of cooperativity by analysing the binding properties of a protein containing a mutated internal histidine. Both mass spectrometry and NMR experiments are consistent with an overall decreased binding affinity of the mutant, while the measured diffusion coefficients of ligand species reveal that the affinity loss concerns essentially one of the two binding sites. We therefore identified a mutation able to disrupt energetic communication functional to efficient binding and conclude that the buried histidine establishes contacts that stabilize the ternary complex.

  13. Acute bile nephropathy secondary to anabolic steroids.

    PubMed

    Alkhunaizi, Ahmed M; ElTigani, Mohamed A; Rabah, Rola S; Nasr, Samih H

    2016-02-01

    Renal dysfunction in cholestatic liver disease is multifactorial. Acute kidney injury may develop secondary to renal vasoconstriction in the setting of peripheral vasodilation and relative hypovolemia, tubular obstruction by bile casts, and direct tubular toxicity from bile. Anabolic steroids are frequently used by athletes to boost endurance and increase muscle mass. These agents are a recently recognized cause of hepatotoxicity and jaundice and may lead to acute kidney injury. To increase awareness about this growing problem and to characterize the pathology of acute kidney injury in this setting, we report on a young male who developed acute kidney injury in the setting of severe cholestatic jaundice related to ingestion of anabolic steroids used for bodybuilding. Kidney biopsy showed bile casts within distal tubular lumina, filamentous bile inclusions within tubular cells, and signs of acute tubular injury. This report supports the recently re-emerged concept of bile nephropathy cholemic nephrosis.

  14. Spontaneous rupture of the common bile duct.

    PubMed

    Kyzer, S; Bayer, I; Chaimoff, C

    1986-01-01

    Spontaneous rupture of the common bile duct in adults is very rare. The authors report only the 14th case in the Western literature. A 25-year-old woman had signs of peritonitis suggestive of a perforated appendix, but at operation the appendix appeared normal and a large amount of bile was found in the peritoneal cavity. A 2-mm tear was found on the anterior wall of the common bile duct. The patient recovered without complications after T-tube drainage and cholecystectomy. In this patient none of the factors thought to cause spontaneous rupture of the common bile duct were present, so the authors conclude that the case may be classified as idiopathic spontaneous rupture of the common bile duct. PMID:3940592

  15. Synthesis of sulfonate analogs of bile acids.

    PubMed

    Kihira, K; Mikami, T; Ikawa, S; Okamoto, A; Yoshii, M; Miki, S; Mosbach, E H; Hoshita, T

    1992-04-01

    Sulfonate analogs of C23 and C24 bile acids were synthesized from norcholic, norchenodeoxycholic, norursodeoxycholic, nordeoxycholic, norhyodeoxycholic, cholic, deoxycholic, hyodeoxycholic, and lithocholic acids. The principal reactions used were (1) reduction of the bile acids with NaBH4 to the corresponding bile alcohols, (2) selective tosylation of the terminal hydroxyl group, (3) iodination of the tosyl esters with NaI, and (4) treatment of the iodides with Na2SO3 to form the sulfonate analogs of the bile acids. The sulfonate analogs showed polarity similar to that of taurine-conjugated bile acids on thin-layer chromatography. The carbon 13 nuclear magnetic resonance spectral data for the sulfonate analogs were tabulated.

  16. Acute bile nephropathy secondary to anabolic steroids.

    PubMed

    Alkhunaizi, Ahmed M; ElTigani, Mohamed A; Rabah, Rola S; Nasr, Samih H

    2016-02-01

    Renal dysfunction in cholestatic liver disease is multifactorial. Acute kidney injury may develop secondary to renal vasoconstriction in the setting of peripheral vasodilation and relative hypovolemia, tubular obstruction by bile casts, and direct tubular toxicity from bile. Anabolic steroids are frequently used by athletes to boost endurance and increase muscle mass. These agents are a recently recognized cause of hepatotoxicity and jaundice and may lead to acute kidney injury. To increase awareness about this growing problem and to characterize the pathology of acute kidney injury in this setting, we report on a young male who developed acute kidney injury in the setting of severe cholestatic jaundice related to ingestion of anabolic steroids used for bodybuilding. Kidney biopsy showed bile casts within distal tubular lumina, filamentous bile inclusions within tubular cells, and signs of acute tubular injury. This report supports the recently re-emerged concept of bile nephropathy cholemic nephrosis. PMID:26587777

  17. Aminoalkylmethacrylate copolymer E improves oral bioavailability of YM466 by suppressing drug-bile interaction.

    PubMed

    Takemura, Shigeo; Kondo, Hiromu; Watanabe, Shunsuke; Sako, Kazuhiro; Ogawara, Ken-Ichi; Higaki, Kazutaka

    2013-09-01

    The aim of this study was to find out polymeric compounds that can inhibit the interaction between YM466, a novel anticoagulant, and bile to improve its oral bioavailability. In vitro ultrafiltration method using extract gall powder was useful to detect the formation of insoluble complex of YM466 with bile and also used to select a polymer that can inhibit the interaction between YM466 and bile. The in vitro studies revealed that aminoalkylmethacrylate (AAM) copolymer E, a polymethacrylate, dose-dependently inhibited the interaction between YM466 and bile and that this polymer could interact with bile salt, but not with YM466, possibly by electrostatic and/or hydrophobic interactions. The coadministration of AAM copolymer E with YM466 to rats dose-dependently increased the plasma concentration of YM466 and it was found that the oral dose of the polymer three times of YM466 (polymer to drug ratio in weight, P-D ratio, 3) significantly increased AUC0-1 h of YM466 to 2.6-fold of that of YM466 alone. Considering the condition of therapeutic use of YM466 and the maximum tolerated dose of the polymer, the formulation of P-D ratio 3 would be clinically practical and promising from the viewpoint of safety.

  18. Effects of ion substitution on bile acid-dependent and -independent bile formation by rat liver.

    PubMed Central

    Van Dyke, R W; Stephens, J E; Scharschmidt, B F

    1982-01-01

    To characterize the transport mechanisms responsible for formation of canalicular bile, we have examined the effects of ion substitution on bile acid-dependent and bile acid-independent bile formation by the isolated perfused rat liver. Complete replacement of perfusate sodium with choline and lithium abolished taurocholate-induced choleresis and reduced biliary taurocholate output by greater than 70%. Partial replacement of perfusate sodium (25 of 128 mM) by choline reduced bile acid-independent bile formation by 30% and replacement of the remaining sodium (103 mM) by choline reduced bile acid-independent bile formation by an additional 64%. In contrast, replacement of the remaining sodium (103 mM) by lithium reduced bile acid-independent bile formation by only an additional 20%, while complete replacement of sodium (128 mM) by lithium reduced bile formation by only 17%, and lithium replaced sodium as the predominant biliary cation. Replacement of perfusate bicarbonate by Tricine, a zwitterionic amino acid buffer, decreased bile acid-independent bile formation by greater than or equal to 50% and decreased biliary bicarbonate output by approximately 60%, regardless of the accompanying cation. In separate experiments, replacement of sodium by lithium essentially abolished Na,K-ATPase activity measured either as ouabain-suppressible ATP hydrolysis in rat liver or kidney homogenates, or as ouabain-suppressible 86Rb uptake by cultured rat hepatocytes. These studies indicate that bile acid(taurocholate)-dependent bile formation by rat liver exhibits a specific requirement for sodium, a finding probably attributable to the role(s) of sodium in hepatic sodium-coupled taurocholate uptake and/or in maintenance of Na,K-ATPase activity. The surprising finding that bile acid-independent bile formation was substantially unaltered by complete replacement of sodium with the permeant cation lithium does not appear to be explained by Na,K-ATPase-mediated lithium transport. Although

  19. Comparative estimation of use potentialities of salt-accumulating and salt-eliminating halophytes for inclusion of NaCl contained in human mineralized urine in BLSS's mass exchange

    NASA Astrophysics Data System (ADS)

    Tikhomirova, Natalia; Ushakova, Sofya; Kudenko, Yurii; Griboskaya, Illiada; Shklavtsova, Ekaterina; Balnokin, Yurii; Popova, Larissa; Myasoedov, Nikolay; Gros, Jean-Bernard; Lasseur, Christophe

    Comparative potentialities of different halophytes' cultivation on a human mineralized urine containing NaCl with the aim of this salt inclusion into the intrasystem BLSS mass exchange were investigated. Two halophyte species were studied namely, salt-accumulating (Salicornia europaea) and salt-eliminating (Limonium gmelinii). During the first two vegetation weeks the plants had been grown on the Knop solution; then a daily norm of the human mineralized urine was gradually added in the experiment solutions. During vegetation the model solutions simulating the urine mineral composition were gradually added in the control solutions. The NaCl concentration in the experiment and control solutions of the first treatment was 9 g/l and that of the second treatment was 20 g/l. The mineralized human urine exposed some inhibitory action on Salicornia europaea and Limonium gmelinii plants. The experiment plants' productivity was lower in comparison with the control. As far as Limonium gmelinii appears to be a perennial plant the growth rate and productivity of this halophyte species was signifi- cantly lower in comparison with Salicornia europaea. Na content in Salicornia europaea plants was higher in comparison with sodium amount emitted by Limonium gmelinii. Consequently Salicornia europaea appears to be a more perspective halophyte for its further use in BLSS aiming at involvement of sodium chloride contained in human liquid wastes in intrasystem mass exchange.

  20. Sourdough fermentation or addition of organic acids or corresponding salts to bread improves nutritional properties of starch in healthy humans.

    PubMed

    Liljeberg, H G; Lönner, C H; Björck, I M

    1995-06-01

    Postprandial blood glucose and insulin responses to barley bread containing organic acids or corresponding salts were evaluated in healthy human subjects. The satiety score and the rate and extent of in vitro starch digestion were also studied. Lactic acid was generated by use of a homofermentative starter culture or added to the dough. In addition, products were baked with Ca-lactate, or with Na-propionate at two different concentrations. Consumption of the product baked with a high concentration of Na-propionate significantly lowered the postprandial blood glucose and insulin responses, and significantly prolonged the duration of satiety compared with all other breads. When subjects consumed the breads baked with sourdough, lactic acid and Na-propionate, their glucose and insulin responses were reduced compared with the wholemeal bread alone. The rate of in vitro amylolysis was reduced only by ingestion of the breads containing lactic acid, suggesting that the beneficial impact of Na-propionate on metabolic responses and satiety was related to effects other than a reduced rate of starch hydrolysis. All bread products had a similar concentration of in vitro resistant starch of 1.3-2.1 g/100 g (starch basis). It is concluded that sourdough baking and other fermentation processes may improve the nutritional features of starch. The results also demonstrate that certain salts of organic acids may have metabolic effects.

  1. Food, fibre, bile acids and the pelvic floor: An integrated low risk low cost approach to managing irritable bowel syndrome.

    PubMed

    Philpott, Hamish; Nandurkar, Sanjay; Lubel, John; Gibson, Peter R

    2015-10-28

    Patients presenting with abdominal pain and diarrhea are often labelled as suffering from irritable bowel syndrome, and medications may be used often without success. Advances in the understanding of the causes of the symptoms (including pelvic floor weakness and incontinence, bile salt malabsorption and food intolerance) mean that effective, safe and well tolerated treatments are now available.

  2. Food, fibre, bile acids and the pelvic floor: An integrated low risk low cost approach to managing irritable bowel syndrome

    PubMed Central

    Philpott, Hamish; Nandurkar, Sanjay; Lubel, John; Gibson, Peter R

    2015-01-01

    Patients presenting with abdominal pain and diarrhea are often labelled as suffering from irritable bowel syndrome, and medications may be used often without success. Advances in the understanding of the causes of the symptoms (including pelvic floor weakness and incontinence, bile salt malabsorption and food intolerance) mean that effective, safe and well tolerated treatments are now available. PMID:26525925

  3. Changes in soils and vegetation in a Mediterranean coastal salt marsh impacted by human activities

    NASA Astrophysics Data System (ADS)

    Álvarez-Rogel, J.; Jiménez-Cárceles, F. J.; Roca, M. J.; Ortiz, R.

    2007-07-01

    This paper reports changes in vegetation distribution and species cover in relation to soil factors and hydrology in a semiarid Mediterranean salt marsh adjacent to the Mar Menor saline lagoon. Species cover, soil salinity, and the groundwater level were monitored between 1991 and 1993 and between 2002 and 2004, and total organic carbon, total nitrogen, total phosphorus, nitrates, ammonium and exchangeable phosphorus were measured in the soils in both study periods. In addition, three soil profiles were described in August 1992 and August 2004. The results indicate an elevation of the water table throughout the 13-year period, which was attributable to water flowing from areas with intensive agriculture. Flooding increased and soil salinity dropped in the most saline sites and increased in the least saline ones. The morphology of the soil profiles reflected the increase in flooding periods, due to the appearance of a greyer matrix in the deeper horizons and a more diffuse pattern of Fe mottles. Following these environmental changes, Sarcocornia fruticosa, Phragmites australis and Juncus maritimus strongly expanded at the wettest sites, which led to the disappearance of the original zonation pattern. The cover of Limonium delicatulum, in turn, decreased with the increase in moisture but increased following the increase in salinity. Changes in soil nutrients were only very evident in the sandy soils of the beach, probably due to the influence of organic debris deposited on the shoreline by the storms and due to the strong increase in the colonisation of this habitat by perennial species. According to the results obtained, control measures are needed in order to preserve habitat diversity in this and other salt marshes of this area. Monitoring of the vegetation distribution could be a useful tool to identify environmental impacts, in order to implement remedial actions.

  4. The Bile Response Repressor BreR Regulates Expression of the Vibrio cholerae breAB Efflux System Operon▿ †

    PubMed Central

    Cerda-Maira, Francisca A.; Ringelberg, Carol S.; Taylor, Ronald K.

    2008-01-01

    Enteric pathogens have developed several resistance mechanisms to survive the antimicrobial action of bile. We investigated the transcriptional profile of Vibrio cholerae O1 El Tor strain C6706 under virulence gene-inducing conditions in the presence and absence of bile. Microarray analysis revealed that the expression of 119 genes was affected by bile. The mRNA levels of genes encoding proteins involved in transport were increased in the presence of bile, whereas the mRNA levels of genes encoding proteins involved in pathogenesis and chemotaxis were decreased. This study identified genes encoding transcriptional regulators from the TetR family (vexR and breR) and multidrug efflux pumps from the resistance-nodulation-cell division superfamily (vexB and vexD [herein renamed breB]) that were induced in response to bile. Further analysis regarding vexAB and breAB expression in the presence of various antimicrobial compounds established that vexAB was induced in the presence of bile, sodium dodecyl sulfate, or novobiocin and that the induction of breAB was specific to bile. BreR is a direct repressor of the breAB promoter and is able to regulate its own expression, as demonstrated by transcriptional and electrophoretic mobility shift assays (EMSA). The expression of breR and breAB is induced in the presence of the bile salts cholate, deoxycholate, and chenodeoxycholate, and EMSA showed that deoxycholate is able to abolish the formation of BreR-PbreR complexes. We propose that deoxycholate is able to interact with BreR and induce a conformational change that interferes with the DNA binding ability of BreR, resulting in breAB and breR expression. These results provide new insight into a transcriptional regulator and a transport system that likely play essential roles in the ability of V. cholerae to resist the action of bile in the host. PMID:18776020

  5. Protection of dried probiotic bacteria from bile using bile adsorbent resins.

    PubMed

    Mahbubani, Krishnaa T; Slater, Nigel K H; Edwards, Alexander D

    2014-01-25

    Enteric coated oral tablets or capsules can deliver dried live cells directly into the intestine. Previously, we found that a live attenuated bacterial vaccine acquired sensitivity to intestinal bile when dried, raising the possibility that although gastric acid can be bypassed, significant loss of viability might occur on release from an enteric coated oral formulations. Here we demonstrate that some food-grade lyophilised preparations of Lactobacillus casei and Lactobacillus salivarius also show temporary bile sensitivity that can be rapidly reversed by rehydration. To protect dried bacterial cells from temporary bile sensitivity, we propose using bile acid adsorbing resins, such as cholestyramine, which are bile acid binding agents, historically used to lower cholesterol levels. Vcaps™ HPMC capsules alone provided up to 830-fold protection from bile. The inclusion of 50% w/w cholestyramine in Vcaps™ HPMC capsules resulted in release of up to 1700-fold more live Lactobacillus casei into simulated intestinal fluid containing 1% bile, when compared to dried cells added directly to bile. We conclude that delivery of dried live probiotic organisms to the intestine may be improved by providing protection from bile by addition of bile adsorbing resins and the use of HPMC capsules. PMID:24080386

  6. Structure of plant bile pigments

    SciTech Connect

    Schoenleber, R.W.

    1983-12-01

    Selective peptide cleavage has provided a general procedure for the study of the structure, including stereochemistry, of plant bile pigments. The information derived from the synthesis and spectral analysis of a series of 2,3-dihydrodioxobilins allows the determination of the trans relative stereochemistry for ring A of the ..beta../sub 1/-phycocyanobilin from C-phycocyanin as well as for ring A of phytochrome. A complete structure proof of the five phycoerythrobilins attached to the ..cap alpha.. and ..beta.. subunits of B-phycoerythrin is described. One of these tetrapyrroles is doubly-peptide linked to a single peptide chain through two thioethers at the C-3' and C-18' positions. The four remaining phycoerythrobilins are singly-linked to the protein through thioethers at the C-3' position and all possess the probable stereochemistry C-2(R), C-3(R), C-3'(R), and C-16(R).

  7. Chylomicrons enhance endotoxin excretion in bile.

    PubMed Central

    Read, T E; Harris, H W; Grunfeld, C; Feingold, K R; Calhoun, M C; Kane, J P; Rapp, J H

    1993-01-01

    Chylomicrons prevent endotoxin toxicity and increase endotoxin uptake by hepatocytes. As a consequence, less endotoxin is available to activate macrophages, thereby reducing tumor necrosis factor secretion. To determine whether the chylomicron-mediated increase in hepatocellular uptake of endotoxin results in increased endotoxin excretion into bile, we examined bile after endotoxin administration. A sublethal dose (7 micrograms/kg) of 125I-endotoxin was incubated with either rat mesenteric lymph containing nascent chylomicrons (500 mg of chylomicron triglyceride per kg of body weight) or an equal volume of normal saline (controls) for 3 h and then infused into male Sprague-Dawley rats. Bile samples were collected via a common bile duct catheter for 24 h. Infusion of endotoxin incubated with chylomicrons increased biliary excretion of endotoxin by 67% at 3 h (P < or = 0.006) and by 20% at 24 h (P < or = 0.01) compared with infusion of endotoxin incubated in saline. Endotoxin activity, as measured by the Limulus assay, was not detected in the bile of test animals. However, endotoxin activity was detected after hot phenol-water extraction of bile, demonstrating that endotoxin is inactive in the presence of bile but retains bioactivity after hepatic processing. Since the majority of an intravenous endotoxin load has been shown to be cleared by the liver, acceleration of hepatocyte clearance and biliary excretion of endotoxin may represent a component of the mechanism by which chylomicrons protect against endotoxin-induced lethality. PMID:8335381

  8. The lipid flippase heterodimer ATP8B1-CDC50A is essential for surface expression of the apical sodium-dependent bile acid transporter (SLC10A2/ASBT) in intestinal Caco-2 cells.

    PubMed

    van der Mark, Vincent A; de Waart, D Rudi; Ho-Mok, Kam S; Tabbers, Merit M; Voogt, Heleen W; Oude Elferink, Ronald P J; Knisely, A S; Paulusma, Coen C

    2014-12-01

    Deficiency of the phospholipid flippase ATPase, aminophospholipid transporter, class I, type 8B, member 1 (ATP8B1) causes progressive familial intrahepatic cholestasis type 1 (PFIC1) and benign recurrent intrahepatic cholestasis type 1 (BRIC1). Apart from cholestasis, many patients also suffer from diarrhea of yet unknown etiology. Here we have studied the hypothesis that intestinal ATP8B1 deficiency results in bile salt malabsorption as a possible cause of PFIC1/BRIC1 diarrhea. Bile salt transport was studied in ATP8B1-depleted intestinal Caco-2 cells. Apical membrane localization was studied by a biotinylation approach. Fecal bile salt and electrolyte contents were analyzed in stool samples of PFIC1 patients, of whom some had undergone biliary diversion or liver transplantation. Bile salt uptake by the apical sodium-dependent bile salt transporter solute carrier family 10 (sodium/bile acid cotransporter), member 2 (SLC10A2) was strongly impaired in ATP8B1-depleted Caco-2 cells. The reduced SLC10A2 activity coincided with strongly reduced apical membrane localization, which was caused by impaired apical membrane insertion of SLC10A2. Moreover, we show that endogenous ATP8B1 exists in a functional heterodimer with transmembrane protein 30A (CDC50A) in Caco-2 cells. Analyses of stool samples of post-transplant PFIC1 patients demonstrated that bile salt content was not changed, whereas sodium and chloride concentrations were elevated and potassium levels were decreased. The ATP8B1-CDC50A heterodimer is essential for the apical localization of SLC10A2 in Caco-2 cells. Diarrhea in PFIC1/BRIC1 patients has a secretory origin to which SLC10A2 deficiency may contribute. This results in elevated luminal bile salt concentrations and consequent enhanced electrolyte secretion and/or reduced electrolyte resorption.

  9. cAMP target sequences enhCRE and CNRE sense low-salt intake to increase human renin gene expression in vivo.

    PubMed

    Desch, Michael; Harlander, Sabine; Neubauer, Björn; Gerl, Melanie; Germain, Stephane; Castrop, Hayo; Todorov, Vladimir T

    2011-05-01

    This study aimed to assess the role of cAMP target sequences enhancer cAMP response element (enhCRE) and cAMP and overlapping negative response element (CNRE) in the control of human renin gene (REN) in vivo. enhCRE and CNRE were silenced by mutations in a 12.2-kb human renin promoter fused to LacZ reporter gene. This construct was used to generate transgenic mice (RENMut-LacZ). The expression of the transgene was correctly targeted to the juxtaglomerular portions of renal afferent arterioles which express endogenous mouse renin. Therefore, enhCRE and CNRE do not seem to be relevant for the control of the cell-specific expression of the human renin gene. The β-adrenoreceptor agonist isoproterenol (10 mg/kg/day, for 2 days) stimulated the endogenous renin, but not the LacZ mRNA expression. Treatment of RENMut-LacZ mice with the angiotensin converting enzyme inhibitor (enalapril 10 mg/kg/day, for 7 days) or their crossing to angiotensin receptor type 1a knockout mice led to increased renin and LacZ mRNA levels. Renin expression was upregulated by low-salt diet (0.03% NaCl, for 10 days) and downregulated by high-salt diet (4% NaCl, for 10 days). In contrast, low-salt diet did not influence, while high-salt diet inhibited the expression of LacZ. In summary, enhCRE and CNRE appear to be necessary for the transactivation of the human renin gene through β-adrenoreceptors and by low-salt diet. Our data also suggest that different intracellular mechanisms mediate the effect of low- and high-salt intake on renin expression in vivo.

  10. History of Hepatic Bile Formation: Old Problems, New Approaches

    ERIC Educational Resources Information Center

    Javitt, Norman B.

    2014-01-01

    Studies of hepatic bile formation reported in 1958 established that it was an osmotically generated water flow. Intravenous infusion of sodium taurocholate established a high correlation between hepatic bile flow and bile acid excretion. Secretin, a hormone that stimulates bicarbonate secretion, was also found to increase hepatic bile flow. The…

  11. An essential role of the CAAT/enhancer binding protein-alpha in the vitamin D-induced expression of the human steroid/bile acid-sulfotransferase (SULT2A1).

    PubMed

    Song, Chung S; Echchgadda, Ibtissam; Seo, Young-Kyo; Oh, Taesung; Kim, Soyoung; Kim, Sung-A; Cho, Sunghwan; Shi, Liheng; Chatterjee, Bandana

    2006-04-01

    The vitamin D receptor (VDR) regulates steroid and drug metabolism by inducing the genes encoding phase I and phase II enzymes. SULT2A1 is a liver- and intestine-expressed sulfo-conjugating enzyme that converts the alcohol-OH of neutral steroids, bile acids, and drugs to water-soluble sulfated metabolites. 1alpha,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] induces SULT2A1 gene transcription after the recruitment of VDR to the vitamin D-responsive chromatin region of SULT2A1. A composite element in human SULT2A1 directs the 1,25-(OH)2D3-mediated induction of natural and heterologous promoters. This element combines a VDR/retinoid X receptor-alpha-binding site [vitamin D response element (VDRE)], which is an imperfect inverted repeat 2 of AGCTCA, and a CAAT/enhancer binding protein (C/EBP)-binding site located 9 bp downstream to VDRE. The binding sites were identified by EMSA, antibody supershift, and deoxyribonuclease I footprinting. C/EBP-alpha at the composite element plays an essential role in the VDR regulation of SULT2A1, because 1) induction was lost for promoters with inactivating mutations at the VDRE or C/EBP element; 2) SULT2A1 induction by 1,25-(OH)2D3 in C/EBP-alpha-deficient cells required the expression of cotransfected C/EBP-alpha; and 3) C/EBP-beta did not substitute for C/EBP-alpha in this regulation. VDR and C/EBP-alpha were recruited concurrently to the composite element along with the coactivators p300, steroid receptor coactivator 1 (SRC-1), and SRC-2, but not SRC-3. VDR and C/EBP-alpha associated endogenously as a DNA-dependent, coimmunoprecipitable complex, which was detected at a markedly higher level in 1,25-(OH)2D3-treated cells. These results provide the first example of the essential role of the interaction in cis between C/EBP-alpha and VDR in directing 1,25-(OH)2D3-induced expression of a VDR target gene.

  12. Functional Environmental Screening of a Metagenomic Library Identifies stlA; A Unique Salt Tolerance Locus from the Human Gut Microbiome

    PubMed Central

    Culligan, Eamonn P.; Sleator, Roy D.; Marchesi, Julian R.; Hill, Colin

    2013-01-01

    Functional environmental screening of metagenomic libraries is a powerful means to identify and assign function to novel genes and their encoded proteins without any prior sequence knowledge. In the current study we describe the identification and subsequent analysis of a salt-tolerant clone from a human gut metagenomic library. Following transposon mutagenesis we identified an unknown gene (stlA, for “salt tolerance locus A”) with no current known homologues in the databases. Subsequent cloning and expression in Escherichia coli MKH13 revealed that stlA confers a salt tolerance phenotype in its surrogate host. Furthermore, a detailed in silico analysis was also conducted to gain additional information on the properties of the encoded StlA protein. The stlA gene is rare when searched against human metagenome datasets such as MetaHit and the Human Microbiome Project and represents a novel and unique salt tolerance determinant which appears to be found exclusively in the human gut environment. PMID:24349412

  13. OST alpha-OST beta: a key membrane transporter of bile acids and conjugated steroids.

    PubMed

    Ballatori, Nazzareno; Li, Na; Fang, Fang; Boyer, James L; Christian, Whitney V; Hammond, Christine L

    2009-01-01

    The organic solute and steroid transporter, Ost alpha-Ost beta, is an unusual heteromeric carrier that appears to play a central role in the transport of bile acids, conjugated steroids, and structurally-related molecules across the basolateral membrane of many epithelial cells. The transporter's substrate specificity, transport mechanism, tissue distribution, subcellular localization, transcriptional regulation, as well as the phenotype of the recently characterized Ost alpha-deficient mice all strongly support this model. In particular, the Ost alpha-deficient mice display a marked defect in intestinal bile acid and conjugated steroid absorption; a decrease in bile acid pool size and serum bile acid levels; altered intestinal, hepatic and renal disposition of known substrates of the transporter; and altered serum triglyceride, cholesterol, and glucose levels. Collectively, the data indicate that Ost alpha-Ost beta is essential for bile acid and sterol disposition, and suggest that the carrier may be involved in human conditions related to imbalances in bile acid or lipid homeostasis.

  14. Serum gamma glutamyl transferase as a specific indicator of bile duct lesions in the rat liver.

    PubMed Central

    Leonard, T. B.; Neptun, D. A.; Popp, J. A.

    1984-01-01

    Serum gamma-glutamyl transferase (GGT), a marker of hepatic injury used extensively in humans, has been used rarely in rats because its specificity has not been previously defined. Studies were designed for investigation of the specificity of serum GGT activity with the use of cell type specific hepatotoxicants in Fischer 344 rats. Single necrogenic doses of CCl4, allyl alcohol (AA), and alpha-naphthylisothiocyanate (ANIT) were used to produce cell specific injury in centrilobular hepatocytes, periportal hepatocytes, and bile duct cells, respectively. Administration of CCl4 markedly increased serum activities of alanine aminotransferase (ALT), alkaline phosphatase (AP), and serum bile acid concentrations within 24 hours but had no effect on serum GGT activity. ANIT treatment increased serum GGT and AP activities and bile acid concentration 24 hours following administration. Allyl alcohol administration increased serum ALT activity but had no effect on GGT activity. Administration of ANIT in the diet at 0.01%, 0.022%, 0.047%, and 0.1% for 2, 4, and 6 weeks produced dose- and time-dependent increases in serum GGT activity which strongly correlated with quantitative increases in hepatic bile duct volume, which was determined morphometrically. These observations support the use of serum GGT activity in the rat as diagnostic of bile duct cell necrosis when increases are detected shortly after the insult and as an indicator of possible bile duct hyperplasia. Images Figure 1 Figure 3 PMID:6147091

  15. Serum gamma glutamyl transferase as a specific indicator of bile duct lesions in the rat liver.

    PubMed

    Leonard, T B; Neptun, D A; Popp, J A

    1984-08-01

    Serum gamma-glutamyl transferase (GGT), a marker of hepatic injury used extensively in humans, has been used rarely in rats because its specificity has not been previously defined. Studies were designed for investigation of the specificity of serum GGT activity with the use of cell type specific hepatotoxicants in Fischer 344 rats. Single necrogenic doses of CCl4, allyl alcohol (AA), and alpha-naphthylisothiocyanate (ANIT) were used to produce cell specific injury in centrilobular hepatocytes, periportal hepatocytes, and bile duct cells, respectively. Administration of CCl4 markedly increased serum activities of alanine aminotransferase (ALT), alkaline phosphatase (AP), and serum bile acid concentrations within 24 hours but had no effect on serum GGT activity. ANIT treatment increased serum GGT and AP activities and bile acid concentration 24 hours following administration. Allyl alcohol administration increased serum ALT activity but had no effect on GGT activity. Administration of ANIT in the diet at 0.01%, 0.022%, 0.047%, and 0.1% for 2, 4, and 6 weeks produced dose- and time-dependent increases in serum GGT activity which strongly correlated with quantitative increases in hepatic bile duct volume, which was determined morphometrically. These observations support the use of serum GGT activity in the rat as diagnostic of bile duct cell necrosis when increases are detected shortly after the insult and as an indicator of possible bile duct hyperplasia. PMID:6147091

  16. Bile acids reduce endocytosis of high-density lipoprotein (HDL) in HepG2 cells.

    PubMed

    Röhrl, Clemens; Eigner, Karin; Fruhwürth, Stefanie; Stangl, Herbert

    2014-01-01

    High-density lipoprotein (HDL) transports lipids to hepatic cells and the majority of HDL-associated cholesterol is destined for biliary excretion. Cholesterol is excreted into the bile directly or after conversion to bile acids, which are also present in the plasma as they are effectively reabsorbed through the enterohepatic cycle. Here, we provide evidence that bile acids affect HDL endocytosis. Using fluorescent and radiolabeled HDL, we show that HDL endocytosis was reduced in the presence of high concentrations of taurocholate, a natural non-cell-permeable bile acid, in human hepatic HepG2 and HuH7 cells. In contrast, selective cholesteryl-ester (CE) uptake was increased. Taurocholate exerted these effects extracellularly and independently of HDL modification, cell membrane perturbation or blocking of endocytic trafficking. Instead, this reduction of endocytosis and increase in selective uptake was dependent on SR-BI. In addition, cell-permeable bile acids reduced HDL endocytosis by farnesoid X receptor (FXR) activation: chenodeoxycholate and the non-steroidal FXR agonist GW4064 reduced HDL endocytosis, whereas selective CE uptake was unaltered. Reduced HDL endocytosis by FXR activation was independent of SR-BI and was likely mediated by impaired expression of the scavenger receptor cluster of differentiation 36 (CD36). Taken together we have shown that bile acids reduce HDL endocytosis by transcriptional and non-transcriptional mechanisms. Further, we suggest that HDL endocytosis and selective lipid uptake are not necessarily tightly linked to each other.

  17. Bile acids reduce endocytosis of high-density lipoprotein (HDL) in HepG2 cells.

    PubMed

    Röhrl, Clemens; Eigner, Karin; Fruhwürth, Stefanie; Stangl, Herbert

    2014-01-01

    High-density lipoprotein (HDL) transports lipids to hepatic cells and the majority of HDL-associated cholesterol is destined for biliary excretion. Cholesterol is excreted into the bile directly or after conversion to bile acids, which are also present in the plasma as they are effectively reabsorbed through the enterohepatic cycle. Here, we provide evidence that bile acids affect HDL endocytosis. Using fluorescent and radiolabeled HDL, we show that HDL endocytosis was reduced in the presence of high concentrations of taurocholate, a natural non-cell-permeable bile acid, in human hepatic HepG2 and HuH7 cells. In contrast, selective cholesteryl-ester (CE) uptake was increased. Taurocholate exerted these effects extracellularly and independently of HDL modification, cell membrane perturbation or blocking of endocytic trafficking. Instead, this reduction of endocytosis and increase in selective uptake was dependent on SR-BI. In addition, cell-permeable bile acids reduced HDL endocytosis by farnesoid X receptor (FXR) activation: chenodeoxycholate and the non-steroidal FXR agonist GW4064 reduced HDL endocytosis, whereas selective CE uptake was unaltered. Reduced HDL endocytosis by FXR activation was independent of SR-BI and was likely mediated by impaired expression of the scavenger receptor cluster of differentiation 36 (CD36). Taken together we have shown that bile acids reduce HDL endocytosis by transcriptional and non-transcriptional mechanisms. Further, we suggest that HDL endocytosis and selective lipid uptake are not necessarily tightly linked to each other. PMID:25010412

  18. Bile canalicular changes and defective bile secretion in Opisthorchis viverrini-infected hamsters.

    PubMed

    Charoensuk, Lakhanawan; Pinlaor, Porntip; Laothong, Umawadee; Yongvanit, Puangrat; Pairojkul, Chawalit; Nawa, Yukifumi; Pinlaor, Somchai

    2014-12-01

    Infection with the liver fluke Opisthorchis viverrini (Digenea) (Poirier, 1886) causes bile duct injury and periductal fibrosis by chronic overproduction of inflammatory-mediators and eventually results in cholangiocarcinoma development. While extensive research works have been done on O. viverrini infection-associated changes of bile ducts and periductal fibrosis, little attention was paid on morphological and biochemical changes of the bile canaliculi (BC), the origin of bile flow. We aimed to investigate the morphological and functional alterations of BC in the liver of hamsters infected with O. viverrini at one and three months post-infection. Ultrastructural changes of BC showed dilatation of BC and significant reduction of the density of microvilli as early as at one month post-infection. Immunohistochemistry revealed that CD10, a BC marker, expression was reduced early as one month post-infection. The mRNA expression of the genes encoding molecules related to bile secretion including bile acid uptake transporters (slc10a1 and slco1a1), bile acid dependent (abcb11) and independent (abcc2) bile flow and bile acid biosynthesis (cyp7a1 and cyp27a1) were significantly decreased at one month post-infection in association with the reduction of bile volume. In contrast, the expression of the mRNA of bile acid regulatory genes (fxr and shp-1) was significantly increased. These changes essentially persisted up to three months post-infection. In conclusion, O. viverrini infection induces morphological and functional changes of BC in association with the decrease of bile volume. PMID:25651692

  19. Phytosterol ester constituents affect micellar cholesterol solubility in model bile.

    PubMed

    Brown, Andrew W; Hang, Jiliang; Dussault, Patrick H; Carr, Timothy P

    2010-09-01

    Plant sterols and stanols (phytosterols) and their esters are nutraceuticals that lower LDL cholesterol, but the mechanisms of action are not fully understood. We hypothesized that intact esters and simulated hydrolysis products of esters (phytosterols and fatty acids in equal ratios) would differentially affect the solubility of cholesterol in model bile mixed micelles in vitro. Sodium salts of glycine- and taurine-conjugated bile acids were sonicated with phosphatidylcholine and either sterol esters or combinations of sterols and fatty acids to determine the amount of cholesterol solubilized into micelles. Intact sterol esters did not solubilize into micelles, nor did they alter cholesterol solubility. However, free sterols and fatty acids altered cholesterol solubility independently (no interaction effect). Equal contents of cholesterol and either campesterol, stigmasterol, sitosterol, or stigmastanol (sitostanol) decreased cholesterol solubility in micelles by approximately 50% compared to no phytosterol present, with stigmasterol performing slightly better than sitosterol. Phytosterols competed with cholesterol in a dose-dependent manner, demonstrating a 1:1 M substitution of phytosterol for cholesterol in micelle preparations. Unsaturated fatty acids increased the micelle solubility of sterols as compared with saturated or no fatty acids. No differences were detected in the size of the model micelles. Together, these data indicate that stigmasterol combined with saturated fatty acids may be more effective at lowering cholesterol micelle solubility in vivo.

  20. Acetic Acid Sclerotherapy for Treatment of a Bile Leak from an Isolated Bile Duct After Laparoscopic Cholecystectomy

    SciTech Connect

    Choi, Gibok Eun, Choong Ki; Choi, HyunWook

    2011-02-15

    Bile leak after laparoscopic cholecystectomy is not uncommon, and it mainly occurs from the cystic duct stump and can be easily treated by endoscopic techniques. However, treatment for leakage from an isolated bile duct can be troublesome. We report a successful case of acetic acid sclerotherapy for bile leak from an isolated bile duct after laparoscopic cholecystectomy.

  1. A Hybrid Cationic Peptide Composed of Human β-Defensin-1 and Humanized θ-Defensin Sequences Exhibits Salt-Resistant Antimicrobial Activity

    PubMed Central

    Nagaraj, Ramakrishnan; Motukupally, Swapna R.

    2014-01-01

    We have designed a hybrid peptide by combining sequences of human β-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics. PMID:25348533

  2. Probing the role of a conserved salt bridge in the intramolecular electron transfer kinetics of human sulfite oxidase.

    PubMed

    Johnson-Winters, Kayunta; Davis, Amanda C; Arnold, Anna R; Berry, Robert E; Tollin, Gordon; Enemark, John H

    2013-08-01

    Sulfite oxidase (SO) is a vital metabolic enzyme that catalyzes the oxidation of toxic sulfite to sulfate. The proposed mechanism of this molybdenum cofactor dependent enzyme involves two one-electron intramolecular electron transfer (IET) steps from the molybdenum center to the iron of the b 5-type heme and two one-electron intermolecular electron transfer steps from the heme to cytochrome c. This work focuses on how the electrostatic interaction between two conserved amino acid residues, R472 and D342, in human SO (hSO) affects catalysis. The hSO variants R472M, R472Q, R472K, R472D, and D342K were created to probe the effect of the position of the salt bridge charges, along with the interaction between these two residues. With the exception of R472K, these variants all showed a significant decrease in their IET rate constants, k et, relative to wild-type hSO, indicating that the salt bridge between residues 472 and 342 is important for rapid IET. Surprisingly, however, except for R472K and R472D, all of the variants show k cat values higher than their corresponding k et values. The turnover number for R472D is about the same as k et, which suggests that the change in this variant is rate-limiting in catalysis. Direct spectroelectrochemical determination of the Fe(III/II) reduction potentials of the heme and calculation of the Mo(VI/V) potentials revealed that all of the variants affected the redox potentials of both metal centers, probably due to changes in their environments. Thus, the position of the positive charge of R472 and that of the negative charge of D342 are both important in hSO, and changing either the position or the nature of these charges perturbs IET and catalysis.

  3. How Is Bile Duct Cancer Diagnosed?

    MedlinePlus

    ... line through which a different kind of contrast dye (IV contrast) is injected. This helps better outline ... common bile duct. A small amount of contrast dye is injected through the tube to help outline ...

  4. Cholangiographic evaluation of bile duct carcinoma

    SciTech Connect

    Nichols, D.A.; MacCarty, R.L.; Gaffey, T.A.

    1983-12-01

    Cholangiograms and clinical histories of 82 patients with biopsy-proved bile duct carcinoma were reviewed. The carcinomas were classified according to morphologic findings and clinical outcome. Ulcerative colitis and antecedent inflammatory disease of the biliary tree, particularly primary sclerosing cholangitis, seem to predispose to the development of bile duct carcinoma. Focal stenotic lesions were the most common morphologic type (62/82). Polypoid carcinomas and diffuse sclerosing carcinomas were less common and of about equal frequency. Prognosis was best for patients with polypoid carcinomas and worst for those with diffuse sclerosing carcinomas. In 69 cases (84%), the tumors involved the intrahepatic or proximal extrahepatic ducts, makin curative resection difficult or impossible. Patients with carcinomas limited to the more distal extrahepatic bile ducts had a longer average survival and a higher probability of surgical cure. Proper management of patients with bile duct carcinoma requires a complete and accurate cholangiographic evaluation of the morphology, location, and extent of the disease.

  5. Treatment Options for Extrahepatic Bile Duct Cancer

    MedlinePlus

    ... checked to measure the amounts of bilirubin and alkaline phosphatase released into the blood by the liver. ... which a stent (a thin, flexible tube or metal tube) is placed in the bile duct to ...

  6. Treatment Option Overview (Extrahepatic Bile Duct Cancer)

    MedlinePlus

    ... checked to measure the amounts of bilirubin and alkaline phosphatase released into the blood by the liver. ... which a stent (a thin, flexible tube or metal tube) is placed in the bile duct to ...

  7. Stages of Extrahepatic Bile Duct Cancer

    MedlinePlus

    ... checked to measure the amounts of bilirubin and alkaline phosphatase released into the blood by the liver. ... which a stent (a thin, flexible tube or metal tube) is placed in the bile duct to ...

  8. Bile Duct (Cholangiocarcinoma) Cancer: Radiation Therapy

    MedlinePlus

    ... form of radiation for bile duct cancer. External beam radiation therapy (EBRT) This type of radiation therapy ... determine the correct angles for aiming the radiation beams and the proper dose of radiation. The treatment ...

  9. Induction of apoptosis by sarijang, a bamboo salt sauce, in U937 human leukemia cells through the activation of caspases.

    PubMed

    Choi, Eun-A; Park, Cheol; Han, Min-Ho; Lee, Jun Hyuk; Kim, Gi-Young; Choi, Byung Tae; Choi, Yung Hyun

    2013-08-01

    Sarijang is a bamboo salt soy sauce, containing extracts of Rhynchosia nulubilis, sulfur-fed duck, dried bark of Ulmus davidiana and Allium sativum, which has been demonstrated to exert anti-inflammatory and antitumor activity. However, the cellular and molecular mechanisms of action of sarijang have not yet been elucidated. In the present study, we investigated the pro-apoptotic effects of sarijang in an in vitro U937 human leukemia cell model. Treatment with sarijang resulted in a concentration-dependent growth inhibition of the cells, coupled with the characteristic morphological features of apoptosis. The induction of the apoptotic cell death of the U937 cells by sarijang exhibited a correlation with the upregulation of death receptor 4 (DR4), the downregulation of members of the inhibitor of apoptosis protein (IAP) family, including survivin and cellular IAP (cIAP)-1, and the cleavage of Bid. Apoptosis-inducing concentrations of sarijang also induced the activation of caspases (caspase-3, -8 and -9), accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase, β-catenin and phospholipase C-γ1. However, the apoptosis induced by sarijang was significantly inhibited by z-VED-fmk, a pan-caspase inhibitor, which demonstrated the importance of caspases in the process. These results suggested that sarijang may be a potential chemotherapeutic agent for use in the control of U937 human leukemia cells. Further studies are required to identify the active compounds in sarijang.

  10. Induction of apoptosis by sarijang, a bamboo salt sauce, in U937 human leukemia cells through the activation of caspases

    PubMed Central

    CHOI, EUN-A; PARK, CHEOL; HAN, MIN-HO; LEE, JUN HYUK; KIM, GI-YOUNG; CHOI, BYUNG TAE; CHOI, YUNG HYUN

    2013-01-01

    Sarijang is a bamboo salt soy sauce, containing extracts of Rhynchosia nulubilis, sulfur-fed duck, dried bark of Ulmus davidiana and Allium sativum, which has been demonstrated to exert anti-inflammatory and antitumor activity. However, the cellular and molecular mechanisms of action of sarijang have not yet been elucidated. In the present study, we investigated the pro-apoptotic effects of sarijang in an in vitro U937 human leukemia cell model. Treatment with sarijang resulted in a concentration-dependent growth inhibition of the cells, coupled with the characteristic morphological features of apoptosis. The induction of the apoptotic cell death of the U937 cells by sarijang exhibited a correlation with the upregulation of death receptor 4 (DR4), the downregulation of members of the inhibitor of apoptosis protein (IAP) family, including survivin and cellular IAP (cIAP)-1, and the cleavage of Bid. Apoptosis-inducing concentrations of sarijang also induced the activation of caspases (caspase-3, -8 and -9), accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase, β-catenin and phospholipase C-γ1. However, the apoptosis induced by sarijang was significantly inhibited by z-VED-fmk, a pan-caspase inhibitor, which demonstrated the importance of caspases in the process. These results suggested that sarijang may be a potential chemotherapeutic agent for use in the control of U937 human leukemia cells. Further studies are required to identify the active compounds in sarijang. PMID:24137193

  11. Anti-inflammatory effects of bamboo salt and sodium fluoride in human gingival fibroblasts--An in vitro study.

    PubMed

    Lee, Hye-Jin; Choi, Choong-Ho

    2015-06-01

    Dental caries preventive agents, such as sodium fluoride (NaF) and bamboo salt (BS), are known to cause cellular growth that is characterized by morphological and gene expre