scholarly journals Hepatic overexpression of Abcb11 in mice promotes the conservation of bile acids within the enterohepatic circulation

2013 ◽  
Vol 304 (2) ◽  
pp. G221-G226 ◽  
Author(s):  
Anne S. Henkel ◽  
Karin E. R. Gooijert ◽  
Rick Havinga ◽  
Renze Boverhof ◽  
Richard M. Green ◽  
...  

The bile salt export pump, encoded by ABCB11, is the predominant canalicular transport protein for biliary bile acid secretion. The level of ABCB11 expression in humans is widely variable yet the impact of this variability on human disease is not well defined. We aim to determine the effect of hepatic Abcb11 overexpression on the enterohepatic circulation (EHC) in mice. We used a stable isotope dilution technique in transgenic mice overexpressing hepatic Abcb11 (TTR- Abcb11) to determine the pool size, fractional turnover rate (FTR), and synthesis rate of the primary bile acid, cholic acid (CA). The gallbladder was cannulated to determine bile flow, bile acid composition, and the biliary secretion rates of CA, total bile acids, phospholipid, and cholesterol. The combined data allowed for estimation of the CA cycling time and the fraction of CA lost per cycle. Hepatic and intestinal gene and protein expression were determined by qPCR and Western blot. Abcb11 overexpression strongly decreased FTR and synthesis rate of CA. Abcb11 overexpression decreased the fraction of CA that was lost per cycle of the EHC. Hepatic expression of Cyp7a1 was suppressed by nearly 50% and ileal expression of FGF15 was increased more than eightfold in TTR- Abcb11 mice. Despite the increased intestinal reabsorption of bile acids, ileal Asbt expression was suppressed. Hepatic Abcb11 overexpression in mice increases the conservation of bile acids within the enterohepatic circulation. These data provide strong evidence for the existence of feed-forward communication between hepatic expression of a bile acid transport protein and the intestine.

2020 ◽  
Vol 46 (1) ◽  
pp. 83-88
Author(s):  
N. B. Gubergrits ◽  
N.V. Byelyayeva ◽  
T. L. Mozhyna ◽  
G. M. Lukashevich ◽  
P. G. Fomenko

After the discovery of the method of ursodeoxycholic acid’s (UDCA) synthesis and the publication of evidence confirming its ability to reduce the lithogenic properties of bile, active clinical use of UDCA began in the world. This drug, which has pleiotropic effect (choleretic, cytoprotective, immunomodulatory, antiapoptic, litholytic, hypocholesterolemic), has proven its effectiveness in the treatment various diseases: primary biliary cholangitis, intrahepatic cholestasis of pregnancy, gallstone disease. Being a tertiary bile acid, UDCA stimulates bile acid synthesis by reducing the circulating fibroblast growth factor 19 and inhibiting the activation of the farnesoid X-receptor (FXR), which leads to the induction of cholesterol-7α-hydroxylase, a key enzyme in the synthesis of bile acid de novo, mediating the conversion of cholesterol into bile acids. Changes in the formation of bile acids and cholesterol while taking UDCA intake is accompanied by activation of the main enzyme of cholesterol synthesis - 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). Under the influence of UDCA the activity of stearoyl-Coa desaturase (SCD) in visceral white adipose tissue increases. According to studies conducted in 2019, UDCA improves lipid metabolism by regulating the activity of the ACT/mTOR signaling pathway, reduces the synthesis of cholesterol, decreases the fractional synthesis rate of cholesterol and the fractional synthesis rate of triglycerides. It has been proved that UDCA is accompanied by a decrease in the level of total cholesterol and low density lipoprotein cholesterol.


Author(s):  
Wojciech Jelski ◽  
Joanna Piechota ◽  
Karolina Orywal ◽  
Barbara Mroczko

Introduction: Intrahepatic cholestasis of pregnancy (ICP) is the liver disorder in the second or early third trimester of pregnancy. It is characterized by pruritus with increased serum bile acids concentration and other liver function tests. ICP  is connected with increased risk of fetal mortality, but is unfortunately detected quite late. Therefore, it is important to recognize the disease in its early stages. We aimed to investigate the serum alcohol dehydrogenase (ADH) activity and compare it with the concentration of total bile acid (TBA) in women with ICP. Methods: Serum samples were taken for routine investigation from 80 pregnancies with ICP in the second or third trimester of pregnancy and from 80 healthy pregnant women in the same time of pregnancy. For measurement of class I activity we used the spectrofluorometric methods. The total ADH activitiy was measured by the photometric method. Results: The analysis of results shows a statistically significant increase in the activity of ADH I and ADH total (about 60% and 41.3%, respectively). Activity of ADH I well correlated with aminotransferases (alanine ALT and aspartate AST) and total bile acids (TBA) concentration. The total ADH activity was also positively correlated with ALT, AST and total bile acids. Conclusion: We can state that the activity of class I alcohol dehydrogenase isoenzyme in the sera of patients with ICP is increased and seems to be a good indicator of liver cell destruction during this disease and is comparable with the value of other markers.


2020 ◽  
Vol 18 (5) ◽  
pp. 36-41
Author(s):  
V.P. Novikova ◽  
◽  
L.N. Belousova ◽  

Bile acid diarrhoea is a common cause of chronic diarrhoea associated with disturbance of the enterohepatic circulation: either excessive biosynthesis/secretion of bile acids or disordered absorption of bile acids in the ileum. At the same time bile acid diarrhoea is an insufficiently studied, frequently underestimated condition, and the questions remain concerning its diagnosis and management. The work discusses the main groups of causes of this pathology, modern diagnostic methods and the difficulties of a differential search. Also, the article offers information about the diet therapy of bile duct diarrhoea and the main groups of administered medications, in particular, modern enterosorbents.


Author(s):  
Peijie Wu ◽  
Ling Qiao ◽  
Han Yu ◽  
Hui Ming ◽  
Chao Liu ◽  
...  

Cholestasis is a kind of stressful syndrome along with liver toxicity, which has been demonstrated to be related to fibrosis, cirrhosis, even cholangiocellular or hepatocellular carcinomas. Cholestasis usually caused by the dysregulated metabolism of bile acids that possess high cellular toxicity and synthesized by cholesterol in the liver to undergo enterohepatic circulation. In cholestasis, the accumulation of bile acids in the liver causes biliary and hepatocyte injury, oxidative stress, and inflammation. The farnesoid X receptor (FXR) is regarded as a bile acid–activated receptor that regulates a network of genes involved in bile acid metabolism, providing a new therapeutic target to treat cholestatic diseases. Arbutin is a glycosylated hydroquinone isolated from medicinal plants in the genus Arctostaphylos, which has a variety of potentially pharmacological properties, such as anti-inflammatory, antihyperlipidemic, antiviral, antihyperglycemic, and antioxidant activity. However, the mechanistic contributions of arbutin to alleviate liver injury of cholestasis, especially its role on bile acid homeostasis via nuclear receptors, have not been fully elucidated. In this study, we demonstrate that arbutin has a protective effect on α-naphthylisothiocyanate–induced cholestasis via upregulation of the levels of FXR and downstream enzymes associated with bile acid homeostasis such as Bsep, Ntcp, and Sult2a1, as well as Ugt1a1. Furthermore, the regulation of these functional proteins related to bile acid homeostasis by arbutin could be alleviated by FXR silencing in L-02 cells. In conclusion, a protective effect could be supported by arbutin to alleviate ANIT-induced cholestatic liver toxicity, which was partly through the FXR pathway, suggesting arbutin may be a potential chemical molecule for the cholestatic disease.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Stef De Lombaerde ◽  
Ken Kersemans ◽  
Sara Neyt ◽  
Jeroen Verhoeven ◽  
Christian Vanhove ◽  
...  

Introduction. An in vivo determination of bile acid hepatobiliary transport efficiency can be of use in liver disease and preclinical drug development. Given the increased interest in bile acid Positron Emission Tomography- (PET-) imaging, a further understanding of the impact of 18-fluorine substitution on bile acid handling in vitro and in vivo can be of significance. Methods. A number of bile acid analogues were conceived for nucleophilic substitution with [18F]fluoride: cholic acid analogues of which the 3-, 7-, or 12-OH function is substituted with a fluorine atom (3α-[18F]FCA; 7β-[18F]FCA; 12β-[18F]FCA); a glycocholic and chenodeoxycholic acid analogue, substituted on the 3-position (3β-[18F]FGCA and 3β-[18F]FCDCA, resp.). Uptake by the bile acid transporters NTCP and OATP1B1 was evaluated with competition assays in transfected CHO and HEK cell lines and efflux by BSEP in membrane vesicles. PET-scans with the tracers were performed in wild-type mice (n=3 per group): hepatobiliary transport was monitored and compared to a reference tracer, namely, 3β-[18F]FCA. Results. Compounds 3α-[18F]FCA, 3β-[18F]FGCA, and 3β-[18F]FCDCA were synthesized in moderate radiochemical yields (4–10% n.d.c.) and high radiochemical purity (>99%); 7β-[18F]FCA and 12β-[18F]FCA could not be synthesized and included further in this study. In vitro evaluation showed that 3α-FCA, 3β-FGCA, and 3β-FCDCA all had a low micromolar Ki-value for NTCP, OATP1B1, and BSEP. In vivo, 3α-[18F]FCA, 3β-[18F]FGCA, and 3β-[18F]FCDCA displayed hepatobiliary transport with varying efficiency. A slight yet significant difference in uptake and efflux rate was noticed between the 3α-[18F]FCA and 3β-[18F]FCA epimers. Conjugation of 3β-[18F]FCA with glycine had no significant effect in vivo. Compound 3β-[18F]FCDCA showed a significantly slower hepatic uptake and efflux towards gallbladder and intestines. Conclusion. A set of 18F labeled bile acids was synthesized that are substrates of the bile acid transporters in vitro and in vivo and can serve as PET-biomarkers for hepatobiliary transport of bile acids.


2019 ◽  
Vol 8 (6) ◽  
pp. 815 ◽  
Author(s):  
Hsien-Hao Huang ◽  
Wei-Jei Lee ◽  
Shu-Chun Chen ◽  
Tung-Fang Chen ◽  
Shou-Dong Lee ◽  
...  

Background: Sleeve gastrectomy (SG) is an effective treatment for obesity and type 2 diabetes mellitus (T2DM), and non-alcoholic fatty liver disease (NAFLD); however, the mechanism is not completely understood. Bile acids and fibroblast growth factors (FGFs) are involved in the regulation of energy metabolism. Methods: We investigated the roles of total bile acid and FGF 19 in T2DM remission and NAFLD improvement in obese subjects undergoing SG. A total of 18 patients with obesity and T2DM undergoing laparoscopic SG were enrolled in this study. Serial plasma total bile acid and FGF 19 levels were measured, while the fatty liver index was calculated before and after surgery. Results: The FGF 19 level significantly increased, and the total bile acid level and fatty liver index decreased 1 year after surgery. The complete T2DM remission rate was 66.7% one year after surgery; the complete remitters had significantly lower FGF 19 levels and higher insulin levels than the non-complete remitters. The complete remitters also had significantly decreased total bile acid levels and increased FGF 19 levels 1 year after surgery compared with those before surgery. The fatty improvers had significantly decreased total bile acid levels and increased FGF 19 levels 1 year after surgery compared with those before surgery. Conclusion: The total bile acids level and fatty liver index decreased, and the FGF 19 levels increased 1 year after SG. Both T2DM complete remitters and NAFLD improvers showed significantly decreased total bile acid levels and increased FGF 19 levels 1 year after SG. Plasma total bile acids and FGF 19 might have roles in T2DM remission and NAFLD improvement. Low preoperative FGF 19 levels might be a predictor for NAFLD improvement after SG.


2020 ◽  
Vol 319 (5) ◽  
pp. G619-G625
Author(s):  
Ivo P. van de Peppel ◽  
Henkjan J. Verkade ◽  
Johan W. Jonker

The enterohepatic circulation of bile acids comprises a tightly regulated process of hepatic bile acid secretion, intestinal reabsorption and transport back to the liver. Disruption of this process has significant consequences for gastrointestinal, liver and whole body homeostasis and therefore offers opportunities for therapeutic intervention. In this review we discuss the effects of (pharmacological) interruption of the enterohepatic circulation at different levels. Recently, several studies have been published on ileal interruption of the enterohepatic circulation of bile acids, targeting the apical-sodium dependent bile acid transporter (ASBT, SLC10A2), as therapy for various diseases. However, ambiguous results have been reported and in-depth mechanistic insights are lacking. Here we discuss these novel studies and review the current knowledge on the consequences of ASBT inhibition and its potential effects on physiology and metabolism.


2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Lien Van den Bossche ◽  
Pieter Hindryckx ◽  
Lindsey Devisscher ◽  
Sarah Devriese ◽  
Sophie Van Welden ◽  
...  

ABSTRACT The promising results seen in studies of secondary bile acids in experimental colitis suggest that they may represent an attractive and safe class of drugs for the treatment of inflammatory bowel diseases (IBD). However, the exact mechanism by which bile acid therapy confers protection from colitogenesis is currently unknown. Since the gut microbiota plays a crucial role in the pathogenesis of IBD, and exogenous bile acid administration may affect the community structure of the microbiota, we examined the impact of the secondary bile acid ursodeoxycholic acid (UDCA) and its taurine or glycine conjugates on the fecal microbial community structure during experimental colitis. Daily oral administration of UDCA, tauroursodeoxycholic acid (TUDCA), or glycoursodeoxycholic acid (GUDCA) equally lowered the severity of dextran sodium sulfate-induced colitis in mice, as evidenced by reduced body weight loss, colonic shortening, and expression of inflammatory cytokines. Illumina sequencing demonstrated that bile acid therapy during colitis did not restore fecal bacterial richness and diversity. However, bile acid therapy normalized the colitis-associated increased ratio of Firmicutes to Bacteroidetes. Interestingly, administration of bile acids prevented the loss of Clostridium cluster XIVa and increased the abundance of Akkermansia muciniphila, bacterial species known to be particularly decreased in IBD patients. We conclude that UDCA, which is an FDA-approved drug for cholestatic liver disorders, could be an attractive treatment option to reduce dysbiosis and ameliorate inflammation in human IBD. IMPORTANCE Secondary bile acids are emerging as attractive candidates for the treatment of inflammatory bowel disease. Although bile acids may affect the intestinal microbial community structure, which significantly contributes to the course of these inflammatory disorders, the impact of bile acid therapy on the fecal microbiota during colitis has not yet been considered. Here, we studied the alterations in the fecal microbial abundance in colitic mice following the administration of secondary bile acids. Our results show that secondary bile acids reduce the severity of colitis and ameliorate colitis-associated fecal dysbiosis at the phylum level. This study indicates that secondary bile acids might act as a safe and effective drug for inflammatory bowel disease.


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