Ursodeoxycholic acid improves gastrointestinal motility defects in gallstone patients

AIM: To simultaneously evaluate the presence of defects in gallbladder and gastric emptying, as well as in intestinal transit in gallstone patients (GS) and the effect of chronic ursodeoxycholic acid (UDCA) administration on these parameters and on serum bile acids and clinical outcome in GS and controls (CTR). METHODS: After a standard liquid test meal, gallbla-dder and gastric emptying (by ultrasound), oroileal transit time (OITT) (by an immunoenzymatic technique) and serum bile acids (by HPLC) were evaluated before and after 3 mo of UDCA (12 mg/kg bw/d) or placebo administration in 10 symptomatic GS and 10 matched healthy CTR. RESULTS: OITT was longer in GS than in CTR (P < 0.0001); UDCA significantly reduced OITT in GS (P < 0.0001), but not in CTR. GS had longer gastric half-emptying time (t1/2) than CTR (P < 0.0044) at baseline; after UDCA, t1/2 significantly decreased (P < 0.006) in GS but not in CTR. Placebo administration had no effect on gastric emptying and intestinal transit in both GS and CTR. CONCLUSION: The gallstone patient has simultaneous multiple impairments of gallbladder and gastric emptying, as well as of intestinal transit. UDCA administration restores these defects in GS, without any effect in CTR. These results confirm the pathogenetic role of gastrointestinal motility in gallstone disease and suggest an additional mechanism of action for UDCA in reducing bile cholesterol supersaturation.

High level of deoxycholic acid in human bile does not promote cholesterol gallstone formation

AIM:To study whether patients with excess deoxycholic acid (DCA) differ from those with normal percentage of DCA with respect to biliary lipid composition and cholesterol saturation of gallbladder bile. METHODS:Bile was collected during operation through puncturing into the gallbladder from 122 cholesterol gallstone patients and 46 gallstone-free subjects undergoing cholecystectomy.Clinical data,biliary lipids,bile add composition, presence of crystals and nucleation time were analyzed. RESULTS:A subgroup of gallstone patients displayed a higher proportion of DCA in bile than gallstone free subjects. By choosing a cut-off level of the 90th percentile,a group of 13 gallstone patients with high DCA levels (mean 50 percent of total bile acids) and a large group of 109 patients with normal DCA levels (mean 21 percent of total bile acids) were obtained.The mean age of the patients with high DCA levels was higher than that of the group with normal levels (mean age:62 years vs45 years) and so was the mean BMI (28.3 vs.24.7).Plasma levels of cholesterol and triglycerides were slightly higher in the DCA excess groups compared with those in the normal DCA group.There was no difference in biliary lipid composition,cholesterol saturation,nucleation time or occurrence of cholesterol crystals in bile between patients with high and normal levels of DCA. CONCLUSION:Gallstone patients with excess DCA were of older age and had higher BMI than patients with normal DCA.The two groups of patients did not differ with respect to biliary lipid composition,cholesterol saturation,nucleation time or occurrence of cholesterol crystals.It is concluded that DCA in bile does not seem to contribute to gallstone formation in cholesterol gallstone patients.

Microwave assisted one-pot synthesis of novel molecular clefts with only one chiral arm based on deoxycholic acid

A rapid, safe, and efficient method for the synthesis of novel molecular clefts based on deoxycholic acid was reported. Seven new molecular clefts have been synthesized in good yields （89-98%）. This method proved to be extremely simple and highly efficient. The structures of these receptors were confirmed by 1H NMR, IR, MS spectra and elemental analysis. 2007 Zhi Gang Zhao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Design and synthesis of novel tweezer anion receptors based on deoxycholic acid

A novel type of molecular tweezer receptors based on deoxycholic acid has been designed and synthesized and their binding properties were examined by UV-vis spectral titration. These molecular tweezers showed a high selectivity toward F^- over Cl^-, Br^-, I^-, AcO^-, H2PO4^-.

Design and Synthesis of Chiral Molecular Tweezers Based on Deoxycholic Acid

A series of new chiral molecular tweezers have been designed and synthesized by using deoxycholic acid as spacer and aromatic amines as arms. Instead of using toxic phosgene, the triphosgene was employed in synthesis of the molecular tweezers receptors. These chiral molecular tweezers showed good enantioselectivity for D-amino acid methyl esters.

Design and synthesis of novel chiral molecular tweezers based on deoxycholic acid

A novel type of chiral molecular tweezers has been designed and synthesized by using deoxycholic acid as backbone and ethanoyl and the chiral unsymmetrical urea unit as arms. Their structures were characterized by 1H NMR, IR, MS spectra and elemental analysis. These molecular tweezers showed good binding ability for neutral molecules and chiral molecules.

Efficient stereoselective hydroxylation of deoxycholic acid by the robust whole-cell cytochrome P450 CYP107D1 biocatalyst

Deoxycholic acid(DCA)has been authorized by the Federal Drug Agency for cosmetic reduction of redundant submental fat.The hydroxylated product(6β-OH DCA)was developed to improve the solubility and pharmaceutic properties of DCA for further applications.Herein,a combinatorial catalytic strategy was applied to construct a powerful Cytochrome P450 biocatalyst(CYP107D1,OleP)to convert DCA to 6β-OH DCA.Firstly,the weak expression of OleP was significantly improved using pRSFDuet-1 plasmid in the E.coli C41(DE3)strain.Next,the supply of heme was enhanced by the moderate overexpression of crucial genes in the heme biosynthetic pathway.In addition,a new biosensor was developed to select the appropriate redox partner.Furthermore,a cost-effective whole-cell catalytic system was constructed,resulting in the highest reported conversion rate of 6β-OH DCA(from 4.8%to 99.1%).The combinatorial catalytic strategies applied in this study provide an efficient method to synthesize high-value-added hydroxylated compounds by P450s.

Fabrication of deoxycholic acid-modified polymeric micelles and their transmembrane transport

Oral administration is the best way for the most patients due to the good compliance,and intestinal epithelium is the main barrier of oral drug absorption.In order to overcome the small intestine epithelial barrier to orally deliver water-insoluble drugs,deoxycholic acid(DA),a substrate of the intestinal bile acid transporters,conjugated poly(2-ethyl-2-oxazoline)-poly(D,L-lactide)(DA-PEOz-PLA)was designed and synthesized,and deoxycholic acid-modified polymeric micelles composed of DA-PEOz-PLA and mPEG-PLA were fabricated to encapsulate model drug coumarin 6(C6)based on intestinal bile acid pathway.The structure of DA-PEOz-PLA was confirmed using 1 H NMR and TLC,and the molecular weight measured by GPC was 10034 g/mol with a PDI of 1.51.The C6-loaded polymeric micelles with drug loading content of 0.085%were characterized to have 40.11 nm in diameter and uniform spherical morphology observed by TEM.Furthermore,the deoxycholic acid-modified polymeric micelles were demonstrated to further enhance the transmembrane transport efficiency.The mechanic study evidenced that anchorage of deoxycholic acid onto the micelles surface enriched their transcellular transport pathway.Therefore,the designed deoxycholic acid-modified polymeric micelles might have a promising potential for oral delivery of water-insoluble drugs.

Oxidative polymerization of hydroquinone using deoxycholic acid supramolecular template

Polyhydroquinone (PHQ) is a redox-active polymer with quinone/hydroquinone redox active units in the main chain and may have potential applications as a mediator in biosensors and biofuel cells. By the oxidative polymerization of hydroquinone (HQ), PHQ can be easily synthesized, but the reaction lacks control over the structure of the product. Deoxycholic acid (DCA) was introduced as a supramolecular template to control the reaction. The reaction rate is 14 times of that in deionized water and twice of that in buffer. The DCA template increases not only the reaction rate, but also the molecular weight of the polymer obtained. The template effect of DCA was attributed to the supramolecular assemblies of DCA formed in the solution. Cyclic voltammetry study indicated the resulting PHQ was redox-active. While the supramolecular assemblies of DCA provided a template for the oxidative polymerization of HQ, the protons released as a by-product of the oxidative polymerization of HQ in turn enhanced the self-assembly of DCA. As a result, DCA microfibers form and separate out of the solution.

Green tea extract and Piper retrofractum attenuate deoxycholic acid-induced damage and enhance the tight junction barrier: An analysis in a Caco-2 cell culture model and a DSS coinduced mouse model

This study investigated the effect of green tea extract(GTE)and green tea-Piper retrofractum complex(GPX),on tight junctions(TJs)in a cellular model of deoxycholic acid(DCA)-induced intestinal barrier disruption and a mouse DSS+DCA-induced colitis model.Green tea and P.retrofractum were extracted and coadministered to examine the bioavailability and effects of combined catechins and piperine on colonic TJ damage.The ability of GPX to alleviate TJ damage was determined by comparing the transepithelial electrical resistance(TEER),FITC-dextran flux,and mRNA expression of TJ-related components and target expression pathway in the GTE and GPX groups.Compared with the DCA-treated group,the GTE-and GPX-treated groups showed significantly enhanced TEER,FITC-dextran flux,and TJ-related mRNA expression(p<0.05).Cell treatment also downregulated the mRNA encoding bile acid receptor and decreased ERK1/2 phosphorylation.Compared with the GTE-treated group,the GPX-treated group showed higher mRNA expression of zonula occludens-1,occludin,claudin-3,and claudin-4;greater restoration of TJs,as determined by immunofluorescence;and better modulation of ERK1/2 activation.In the in vivo model,GPX-pretreated mice showed an improved intestinal damage index and colon length compared with mice in the other colitis-induced groups.Both extracts recovered the distal colon mRNA expression of zonula occludens-1 and claudin-1.These results suggest that GTE improves intestinal health by protecting TJs from secondary bile acid damage and that P.retrofractum may potentiate the bioactivity of green tea catechins.

Bile acids in serum and bile of patients with cholesterol gallstone

IM To analyze serum bile acids and biliary lipids of patients with cholesterol gallstone(CS) and explore the relationship between deoxycholic acid (DCA) and CS disease.METHODS Analysis of bile acids in serum was done with gaschromatography in two groups: CS group (n=151) and control group (n=256). Serum bile acids and biliary lipids were also studied in 90 matched samples..RESULTS The serum DCA was 0955μmol/L±0078μmol/L in CS group, which was more than that of control group (0696μmol/L±0047μmol/L), P<001. The ratio of DCA/chenodeoxycholic acids (CDCA) was 176±030 in CS group, about two times that in control group (092±014). The mole percent of DCA in bile was positively related to cholesterol saturation index (CSI) (P<001) and the mole percent of CDCA in bile negatively to CSI (P=001). There was correlation between the mole percent of DCA, CDCA and cholic acid in bile and in serum.CONCLUSION It is suggested that DCA is lithogenic and the increased amount of DCA or the ratio of DCA/CDCA in serum may be one of the features of cholesterol gallstone patients.

Dietary glycine blunts liver injury after bile duct ligation in rats

AIM： To investigate the effects of （dietary） glycine against oxidant-induced injury caused by bile duct ligation （BDL）.METHODS： Either a diet containing 5% glycine or a standard diet was fed to male Sprague-Dawley （SD） rats. Three days later, BDL or sham-operation was performed. Rats were sacrificed 1 to 3 d after BDL. The influence of deoxycholic acid （DCA） in the presence or absence of glycine on liver cells was determined by measurement of calcium and chloride influx in cultivated Kupffer cells and lactate dehydrogenase （LDH） activity was determined in the supernatant of cultivated hepatocytes.RESULTS： Serum alanine transaminase levels increased to about 600 U/L 1 d alter BDL. However, enzyme release was blunted by about two third in rats receiving glycine. Release of the alkaline phosphatase and aspartate aminotransferase was also blocked significantly in the group fed glycine. Focal necrosis was observed 2 d after BDL. Glycine partially blocked the histopathological changes. Incubation of Kupffer cells with DCA led to increased intracellular calcium that could be blocked by incubation with glycine. However, systemic blockage of Kupffer cells with gadolinium chloride had no effects on transaminase release. Incubation of isolated hepatocytes with DCA led to a significant release of LDH after 4 h. This release was largely blocked when incubation with glycine was performed.CONCLUSION： These data indicate that glycine significantly decreased liver injury, most likely by a direct effect on hepatocytes. Kupffer cells do not appear to play an important role in the pathological changes caused by cholestasis.

Difference and clinical value of metabolites in plasma and feces of patients with alcohol-related liver cirrhosis

BACKGROUND Alterations in plasma and intestinal metabolites contribute to the pathogenesis and progression of alcohol-related liver cirrhosis(ALC).AIM To explore the common and different metabolites in the plasma and feces of patients with ALC and evaluate their clinical implications.METHODS According to the inclusion and exclusion criteria,27 patients with ALC and 24 healthy controls(HCs)were selected,and plasma and feces samples were collected.Liver function,blood routine,and other indicators were detected with automatic biochemical and blood routine analyzers.Liquid chromatography-mass spectrometry was used to detect the plasma and feces metabolites of the two groups and the metabolomics of plasma and feces.Also,the correlation between metabolites and clinical features was analyzed.RESULTS More than 300 common metabolites were identified in the plasma and feces of patients with ALC.Pathway analysis showed that these metabolites are enriched in bile acid and amino acid metabolic pathways.Compared to HCs,patients with ALC had a higher level of glycocholic acid(GCA)and taurocholic acid(TCA)in plasma and a lower level of deoxycholic acid(DCA)in the feces,while L-threonine,L-phenylalanine,and L-tyrosine increased simultaneously in plasma and feces.GCA,TCA,L-methionine,L-phenylalanine,and L-tyrosine in plasma were positively correlated with total bilirubin(TBil),prothrombin time(PT),and maddrey discriminant function score(MDF)and negatively correlated with cholinesterase(CHE)and albumin(ALB).The DCA in feces was negatively correlated with TBil,MDF,and PT and positively correlated with CHE and ALB.Moreover,we established a P/S BA ratio of plasma primary bile acid(GCA and TCA)to fecal secondary bile acid(DCA),which was relevant to TBil,PT,and MDF score.CONCLUSION The enrichment of GCA,TCA,L-phenylalanine,L-tyrosine,and L-methionine in the plasma of patients with ALC and the reduction of DCA in feces were related to the severity of ALC.These metabolites may be used as indicators to evaluate the progression of alcohol-related liver cirrhosis.

Synthesis and Characterization of Chitosan-based Biomateriais Modified with Different Active Groups and Their Relationship with Cytotoxicity

The cytotoxicity profile of three chitosan derivatives with different affinity to water was evaluated in vitro. The derivatives selected were carboxymethylated-chitosan （CMCH）, linoleic acid modifiedchitosan （LACH） and deoxycholic acid modified-chitosan （DACH）, respectively, and the results of FTIR and NMR confirmed the successful modification. Cytotoxicity of these polymers was investigated via the red blood cell lysis assay and the MTT assay. The red blood cell lysis test showed that CH elicited a certain level of red blood cell toxicity, while CMCH, LACH and DACH all displayed low membrane damaging effects, with the hemolysis rates of 2.385%, 1.560% and 4.404%, respectively, which comes well within permissible limit （5%）. The MTT assay revealed that CH exhibited significant inhibitory effect on fibroblast proliferation at higher concentration, while its three derivatives showed no cytotoxicity. CMCH had stimulatory effects on fetal mouse fibroblast proliferation. Differences in cytotoxicity of CH and its derivatives may result from the specific chemical modifications leading to the alteration of molecular charge density and type of the cationic functionalities, structure and sequence, and conformational flexibility.