scholarly journals Effects of clofibrate on some microsomal hydroxylations involved in the formation and metabolism of bile acids in rat liver

1976 ◽  
Vol 156 (2) ◽  
pp. 445-448 ◽  
Author(s):  
B O Angelin ◽  
I Björkhem ◽  
K Einarsson
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Rat Liver ◽  
Lithocholic Acid ◽  
Present Knowledge ◽  
Acid Formation ◽  
Microsomal Metabolism ◽  
Endogenous Cholesterol

1. The liver microsomal metabolism of [4-14C]cholesterol, endogenous cholesterol, 7 α-hydroxy-4-[6 β-3H]cholesten-3-one, 5-β-[7 β-3H]cholestane-3 α, 7 α-diol and [3H]lithocholic acid was studdied in control and clofibrate (ethyl p-chlorophenoxyisobutyrate)-treated rats. 2. The extent of 7 α-hydroxylation of exogenous [414C]cholesterol and endogenous cholesterol, the latter determined with a mass fragmentographic technique, was the same in the two groups of rats. The extent of 12 α-hydroxylation of 7 α-hydroxy-4-cholesten-3-one and 5 β-cholestane-3 α, 7 α-diol was increased by about 60 and 120% respectively by clofibrate treatment. The 26-hydroxylation of 5 β-cholestane-3 α, 7 α-diol was not significantly affected by clofibrate. The 6 β-hydroxylation of lithocholic acid was about 80% higher in the clofibrate-treated animals than in the controls. 3. The results are discussed in the context of present knowledge about the liver microsomal hydroxylating system and bile acid formation in patients with hypercholesterolaemia, treated with clofibrate.

Pharmacological effects of secondary bile acid microparticles in diabetic murine model

2020 ◽  
Vol 16 ◽  
Author(s):  
Armin Mooranian ◽  
Nassim Zamani ◽  
Bozica Kovacevic ◽  
Corina Mihaela Ionescu ◽  
Giuseppe Luna ◽  
...  
Keyword(s):  
Bile Acid ◽  
Blood Glucose ◽  
Bile Acids ◽  
Lithocholic Acid ◽  
Diabetes Treatment ◽  
Secondary Bile Acid ◽  
Glucose Levels ◽  
Anti Inflammatory ◽  
Antidiabetic Effects

Aim: Examine bile acids effects in Type 2 diabetes. Background: In recent studies, the bile acid ursodeoxycholic acid (UDCA) has shown potent anti-inflammatory effects in obese patients while in type 2 diabetics (T2D) levels of the pro-inflammatory bile acid lithocholic acid were increased, and levels of the anti-inflammatory bile acid chenodeoxycholic acid were decreased, in plasma. Objective: Hence, this study aimed to examine applications of novel UDCA nanoparticles in diabetes. Methods: Diabetic balb/c adult mice were divided into three equal groups and gavaged daily with either empty microcapsules, free UDCA, or microencapsulated UDCA over two weeks. Their blood, tissues, urine, and faeces were collected for blood glucose, inflammation, and bile acid analyses. UDCA resulted in modulatory effects on bile acids profile without antidiabetic effects suggesting that bile acid modulation was not directly linked to diabetes treatment. Results: UDCA resulted in modulatory effects on bile acids profile without antidiabetic effects suggesting that bile acid modulation was not directly linked to diabetes treatment. Conclusion: Bile acids modulated the bile profile without affecting blood glucose levels.

scholarly journals Properties of the canalicular bile acid transport system in rat liver

1987 ◽  
Vol 242 (2) ◽  
pp. 465-469 ◽  
Author(s):  
P J Meier ◽  
A S Meier-Abt ◽  
J L Boyer
Keyword(s):  
Bile Acid ◽  
Substrate Specificity ◽  
Bile Acids ◽  
Rat Liver ◽  
Transport System ◽  
Acid Transport ◽  
Bile Acid Transport ◽  
Canalicular Bile ◽  
Disulphonic Acid ◽  
Bile Acid Carrier

4,4-Di-isothiocyanostilbene-2,2′-disulphonic acid inhibition of taurocholate efflux from canalicular vesicles was used to demonstrate that potential driven and ‘carrier’-mediated canalicular excretion of taurocholate occur via a common, rather than two separate, pathways. This electrogenic canalicular bile acid ‘carrier ’ preferentially transports trihydroxylated and conjugated dihydroxylated bile acids, but not the unphysiological oxo bile acids, and possibly extends its substrate specificity to other amphipathic molecules such as sulphobromophthalein.

scholarly journals Human gut bacteria produce TH17-modulating bile acid metabolites

2021 ◽  
Author(s):  
Donggi Paik ◽  
Lina Yao ◽  
Yancong Zhang ◽  
Sena Bae ◽  
Gabriel D. D'Agostino ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Lithocholic Acid ◽  
Retinoic Acid Receptor ◽  
Gut Bacteria ◽  
Orphan Nuclear Receptor ◽  
Human Gut ◽  
Secondary Bile Acid ◽  
Bowel Diseases ◽  
And Function

The microbiota plays a pivotal role in gut immune homeostasis. Bacteria influence the development and function of host immune cells, including T helper cells expressing interleukin-17a (TH17 cells). We previously reported that the bile acid metabolite 3-oxolithocholic acid (3-oxoLCA) inhibits TH17 cell differentiation. While it was suggested that gut-residing bacteria produce 3-oxoLCA, the identity of such bacteria was unknown. Furthermore, it was not clear whether 3-oxoLCA and other immunomodulatory bile acids are associated with gut inflammatory pathologies in humans. Using a high-throughput screen, we identified human gut bacteria and corresponding enzymes that convert the secondary bile acid lithocholic acid into 3-oxoLCA as well as the abundant gut metabolite isolithocholic acid (isoLCA). Like 3-oxoLCA, isoLCA suppressed TH17 differentiation by inhibiting RORγt (retinoic acid receptor-related orphan nuclear receptor γt), a key TH17 cell-promoting transcription factor. Levels of both 3-oxoLCA and isoLCA and the 3α-hydroxysteroid dehydrogenase (3α-HSDH) genes required for their biosynthesis were significantly reduced in patients with inflammatory bowel diseases (IBD). Moreover, levels of these bile acids were inversely correlated with expression of TH17 cell-associated genes. Overall, our data suggest that bacterially produced TH17 cell-inhibitory bile acids may reduce the risk of autoimmune and inflammatory disorders such as IBD.

scholarly journals 1039. Rapid Restoration of Bile Acid Compositions After Treatment with RBX2660 for Recurrent Clostridioides difficile Infection—Results from the PUNCH CD3 Phase 3 Trial

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S610-S610
Author(s):  
Romeo Papazyan ◽  
Bryan Fuchs ◽  
Ken Blount ◽  
Carlos Gonzalez ◽  
Bill Shannon
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Deoxycholic Acid ◽  
Lithocholic Acid ◽  
Point Group ◽  
Bile Acid Metabolism ◽  
Phase 3 ◽  
Clostridioides Difficile ◽  
Clostridioides Difficile Infection ◽  
Time Point

Abstract Background Microbiota-based treatments are increasingly evaluated as a strategy to reduce recurrence of Clostridioides difficile infection (rCDI), and their proposed mechanisms include restoration of the microbiota and microbiota-mediated functions, including bile acid metabolism. RBX2660—a broad-consortium investigational live biotherapeutic—has been evaluated in >600 participants in 6 clinical trials, with consistent reduction of rCDI recurrence. Here we report that fecal bile acid compositions were significantly restored in treatment-responsive participants in PUNCH CD3—a Phase 3 randomized, double-blinded, placebo-controlled trial of RBX2660. Methods PUNCH CD3 participants received a single dose of RBX2660 or placebo between 24 to 72 hours after completing rCDI antibiotic treatment. Clinical response was the absence of CDI recurrence at eight weeks after treatment. Participants voluntarily submitted stool samples prior to blinded study treatment (baseline), 1, 4 and 8 weeks, 3 and 6 months after receiving study treatment. A liquid chromatography tandem mass spectrometry method was developed to extract and quantify 33 bile acids from all participant fecal samples received up to the 8-week time point. Mean bile acid compositions were fit to a Dirichlet multinomial distribution and compared across time points and between RBX2660- and placebo-treated participants. Results Clinically, RBX2660 demonstrated superior efficacy versus placebo (70.4% versus 58.1%). RBX2660-treated clinical responders’ bile acid compositions shifted significantly from before to after treatment. Specifically, primary bile acids predominated before treatment, whereas secondary bile acids predominated after treatment (Figure 1A). These changes trended higher among RBX2660 responders compared to placebo responders. Importantly, median levels of lithocholic acid (LCA) and deoxycholic acid (DCA) showed large, significant increases after treatment (Figure 1B). A. Bile acid compositions before (BL) and up to 8 weeks after RBX2660 treatment among treatment responders. Compositions are shown as the fraction of total bile acids classified as primary or secondary conjugated or deconjugated bile acids. B. Concentrations of lithocholic acid (LCA) and deoxycholic acid (DCA) among RBX2660 treatment responders, shown with individual samples and time point group median with interquartile ranges. Conclusion Among PUNCH CD3 clinical responders, RBX2660 significantly restored bile acids from less to more healthy compositions. These clinically correlated bile acid shifts are highly consistent with results from a prior trial of RBX2660. Disclosures Romeo Papazyan, PhD, Ferring Research Institute (Employee) Bryan Fuchs, PhD, Ferring Pharmaceuticals (Employee) Ken Blount, PhD, Rebiotix Inc., a Ferring Company (Employee)

Identification of unique bile acid-metabolizing bacteria from the microbiome of centenarians

2020 ◽  
Author(s):  
Kenya Honda ◽  
Yuko Sato ◽  
Koji Atarashi ◽  
Damian Plichta ◽  
Yasumichi Arai ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Lithocholic Acid ◽  
Multidrug Resistant ◽  
Bile Acid Metabolism ◽  
Critical Determinant ◽  
Secondary Bile Acid ◽  
Clostridioides Difficile ◽  
Vancomycin Resistant ◽  
Secondary Bile Acids

Abstract Centenarians, or individuals who have lived more than a century, represent the ultimate model of successful longevity associated with decreased susceptibility to ageing-associated illness and chronic inflammation. The gut microbiota is considered to be a critical determinant of human health and longevity. Here we show that centenarians (average 107 yo) have a distinct gut microbiome enriched in microbes capable of generating unique secondary bile acids, including iso-, 3-oxo-, and isoallo-lithocholic acid (LCA), as compared to elderly (85-89 yo) and young (21-55 yo) controls. Among these bile acids, the biosynthetic pathway for isoalloLCA had not been described previously. By screening 68 bacterial isolates from a centenarian’s faecal microbiota, we identified Parabacteroides merdae and Odoribacteraceae strains as effective producers of isoalloLCA. Furthermore, we generated and tested mutant strains of P. merdae to show that the enzymes 5α-reductase (5AR) and 3β-hydroxysteroid dehydrogenase (3βHSDH) were responsible for isoalloLCA production. This secondary bile acid derivative exerted the most potent antimicrobial effects among the tested bile acid compounds against gram-positive (but not gram-negative) multidrug-resistant pathogens, including Clostridioides difficile and vancomycin-resistant Enterococcus faecium. These findings suggest that specific bile acid metabolism may be involved in reducing the risk of pathobiont infection, thereby potentially contributing to longevity.

The function of multidrug resistance-associated protein 3 in the transport of bile acids under normal physiological and lithocholic acid-induced cholestasis conditions

2021 ◽  
Vol 22 ◽  
Author(s):  
Wenyu Wang ◽  
Sijing Zeng ◽  
Ming Hu ◽  
Zhongqiu Liu ◽  
Lingzhi Gong
Keyword(s):  
Multidrug Resistance ◽  
Bile Acid ◽  
Bile Acids ◽  
Physiological Condition ◽  
Lithocholic Acid ◽  
Efflux Transporters ◽  
Valuable Insight ◽  
Wild Type ◽  
Normal Physiological Condition

Background: The role of multidrug resistance-associated protein 3 (Mrp3) in the transport of bile acid (BA) in drug-induced cholestasis have not been well studied. Objective: In this study, wild type and Mrp3 knockout (Mrp3-/- ) mice under normal physiological and lithocholic acid (LCA)-induced cholestatic conditions were employed to investigate the role of Mrp3 in BA transport. Method: The levels of BA in serum, liver, gallbladder, intestine, kidney, feces and urine were quantified in both wild type and Mrp3-/- mice via ultra-high performance liquid chromatography triple quadrupole mass spectrometry (UHPLC-MS/MS). Quantitative real time PCR (RT-PCR) analysis was used to measure the expression of genes related to the transport and synthesis of BA. Results: The results showed that the liver did not suffer more serious damage as a result of cholestasis when Mrp3 was depleted. The level of some individual bile acids changed apparently in the compartments of enterohepatic circulation (EHC) between the two control and model groups, respectively, but the level of serum total bile acid was only slightly reduced for Mrp3-/- groups. In addition, the level of BA-related efflux transporters and synthases increased significantly when Mrp3 was knocked out under normal physiological condition, but negligible alteration of them appeared under cholestatic condition. Conclusion: Our results indicated that Mrp3 could be responsible for the transport of some specific bile acids, and part of the Mrp3 role could be compensated for by other transporters. Moreover, Mrp3 deficiency has a direct effect on the expression of BA-related synthases and efflux transporters under normal physiological condition, but this effect could be less prominent under cholestatic condition. This study could provide much valuable insight into the physiological function of Mrp3 in the transport of bile acids.

scholarly journals Distinct forms of cytochrome P-450 are responsible for 6β-hydroxylation of bile acids and of neutral steroids

1991 ◽  
Vol 275 (1) ◽  
pp. 105-111 ◽  
Author(s):  
P Zimniak ◽  
E J Holsztynska ◽  
A Radominska ◽  
M Iscan ◽  
R Lester ◽  
...  
Keyword(s):  
Bile Acids ◽  
Steroid Hormones ◽  
Rat Liver ◽  
Lithocholic Acid ◽  
Structural Elements ◽  
Differential Inhibition ◽  
Mutual Inhibition ◽  
Hydroxylation Reaction ◽  
Differential Responses ◽  
Cytochrome P 450

Cytochrome P-450-dependent 6 beta-hydroxylation of bile acids in rat liver contributes to the synthesis of the quantitatively important pool of 6-hydroxylated bile acids, as well as to the detoxification of hydrophobic bile acids. The lithocholic acid 6 beta-hydroxylation reaction was investigated and compared with androstenedione 6 beta-hydroxylation. Differential responses of these two activities to inducers and inhibitors of microsomal P-450 enzymes, lack of mutual inhibition by the two substrates and differential inhibition by antibodies raised against several purified hepatic cytochromes P-450 were observed. From these results it was concluded that 6 beta-hydroxylation of lithocholic acid is catalysed by P-450 form(s) different from the subfamily IIIA cytochromes P-450 which are responsible for the bulk of microsomal androstenedione 6 beta-hydroxylation. Similar, but more tentative, results revealed that the 7 alpha-hydroxylation of lithocholic acid and of androstenedione may be also catalysed by distinct P-450 enzymes. The results indicate that cytochromes P-450 hydroxylating bile acids are distinct from analogous enzymes that carry out reactions of the same regio- and stereo-specificity on neutral steroids (steroid hormones). A comparison of pairs of cytochromes P-450 that catalyse the same reaction on closely related steroid molecules will help to define those structural elements in the proteins that determine the recognition of their respective substrates.

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