Influence of ethinyloestradiol propanolsulphonate on serum bile acids in healthy volunteers

Pregnancy-Associated Liver Diseases

The liver disorders unique to pregnancy include hyperemesis gravidarum, intrahepatic cholestasis of pregnancy, acute fatty liver of pregnancy, and preeclampsia-associated hepatic impairment, specifically hemolysis, elevated liver enzymes, and low platelet count syndrome (HELLP). Their importance lies in the significant maternal and fetal/neonatal morbidity and mortality. Expeditious diagnosis and clinical evaluation is critical to ensure timely, appropriate care and minimize risks to the pregnant woman and her fetus/baby. A multidisciplinary approach is essential, including midwives, maternal-fetal-medicine specialists, anesthetists, neonatologists, and hepatologists.

Role of Vitamin B12 and Vitamin D levels in intrahepatic cholestasis of pregnancy and correlation with total bile acid

This study aimed to evaluate the relationship between intrahepatic cholestasis of pregnancy (ICP) and Vitamin D and B12 levels. The study was a retrospective, cross-sectional, case-control study that evaluated 92 ICP cases and 102 pregnant women without any additional disease. ICP cases were grouped as mild and severe according to their total bile acid (TBA) levels, and their relationship with Vitamin D and B12 levels and perinatal outcomes was evaluated. Vitamin D and B12 levels of the ICP group were significantly lower than those of the control group. There was a moderate negative correlation between TBA and Vitamin D levels and a low negative correlation between TBA and Vitamin B12 levels. Adverse neonatal outcomes were significantly higher in the severe ICP group than in the mild ICP group. IMPACT STATEMENTWhat is already known on this subject? The pathophysiology of ICP, which can lead to adverse perinatal outcomes, is not yet fully understood, and there is no preventive treatment.What do the results of this study add? This study showed that Vitamins B12 and D levels were low in women with ICP and that TBA levels were negatively correlated with Vitamin D and B12 levels.What are the implications of these findings for clinical practice and/or further research? This study may guide future studies in terms of explaining the etiopathogenesis of ICP and developing treatment options.

Development of an Adverse Outcome Pathway for Intrahepatic Cholestasis of Pregnancy

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Adverse outcome pathways are an established method for knowledge synthesis in toxicology.

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This method has not yet been applied in the context of clinical research.

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There are opportunities to apply AOPs to the integration and synthesis of biomedical research.

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The AOP developed in this paper is an example of how the method could be used to investigate clinical questions.

Adverse Outcome Pathways (AOPs) are a research synthesis tool, used primarily by toxicologists for numerous applications including: hypothesis generation, data integration, biomarker determination, and identification of gaps in current knowledge. The AOP model provides a means for evaluating critical interactions between stressors and biological systems which result in adversity, meaning there is significant potential value in using this model in clinical research. However, AOPs have so far not been applied in this context, which may be attributable to the fact that the method is not yet streamlined with established practices in evidence-based medicine, such as systematic review.

Here, we present one approach to developing a clinically focused AOP for intrahepatic cholestasis of pregnancy; aiming to enhance understanding of the mechanistic link between this common, gestational liver disease and its association with preterm birth.

Mechanistic aspects of the disease pathogenesis, and use of AOPs to broaden inclusion and improve integration of in vitro and in vivo data in clinical research are discussed.

We also demonstrate for the first time how central components of systematic review can be integrated into the development of an AOP.

Analysis of bile acids in human biological samples by microcolumn separation techniques: A review

Bile acids are a group of compounds essential for lipid digestion and absorption with a steroid skeleton and a carboxylate side chain usually conjugated to glycine or taurine. Bile acids are regulatory molecules for a number of metabolic processes and can be used as biomarkers of various disorders. Since the middle of the twentieth century, the detection of bile acids has evolved from simple qualitative analysis to accurate quantification in complicated mixtures. Advanced methods are required to characterize and quantify individual bile acids in these mixtures. This article overviews the literature from the last two decades (2000-2020) and focuses on bile acid analysis in various human biological samples. The methods for sample preparation, including the sample treatment of conventional (blood plasma, blood serum, and urine) and unconventional samples (bile, saliva, duodenal/gastric juice, feces, etc.) are shortly discussed. Eventually, the focus is on novel analytical approaches and methods for each particular biological sample, providing an overview of the microcolumn separation techniques, such as high-performance liquid chromatography, gas chromatography, and capillary electrophoresis, used in their analysis. This is followed by a discussion on selected clinical applications.

Intrahepatic Cholestasis in Pregnancy: Review of the Literature

Intrahepatic cholestasis of pregnancy (ICP) is the most common hepatic disorder related to pregnancy in women. It usually develops within the third trimester of pregnancy and presents with pruritus as well as elevated levels of bile acid and/or alanine aminotransferase. Clinical signs quickly resolve after delivery; however, there is a high risk of the disorder recurring in subsequent pregnancies. ICP is associated with an increased risk of perinatal complications (premature birth, respiratory disorders, even stillbirth). Elevated levels of gestational hormones and genetic predispositions are important factors for the development of ICP; among the latter, mutations in hepatobiliary transport proteins (multidrug resistance protein 3-MDR3, bile salt export pump- BSEP) play a major role. Clinical and biochemical symptoms of ICP include pruritus and increased levels of total bile acids (TBA). Serum levels of TBA should be monitored in ICP patients throughout the pregnancy as concentrations above 40 μmol/L, which define that severe ICP isassociated with an increased risk of fetal complications. Therapeutic management is aimed at reducing the clinical symptoms, normalizing maternal biochemistry and preventing complications to the fetus. Pharmacological treatment of intrahepatic cholestasis of pregnancy consists of the administration of ursodeoxycholic acid to lower the levels of TBA and possibly reduce pruritus. If the treatment fails, premature delivery should be considered.

Effect of YHHJ on the expression of the hepatocellular bile acid transporters multidrug resistance-associated protein 2 and bile salt export pump in ethinylestradiol-induced cholestasis

The herbal medicine Yin Huang Mixture (YHHJ; patent no. 200910031240.7) is an aqueous extract composed from various herbs, including Artemisia capillaries Thunb, Hypericum japonicum Thunb, Eucommia ulmoides Oliver, Rheum officinale Baill, Gardenia jasminoides Ellis, Poria cocos Wolf and Dictamnus dasycarpus Turcz. Previous studies have indicated that YHHJ treatment has a beneficial effect on ameliorating itching and reducing serum bile acid levels in patients with intrahepatic cholestasis of pregnancy (ICP). However, the molecular mechanisms of action of YHHJ in ICP have not been fully elucidated. Therefore, the present study investigated an experimental hepatocellular cholestasis model to explore the regulatory role of YHHJ on the expression of the bile acid carriers, multidrug resistance-associated protein 2 (MRP2) and the bile salt export pump (BSEP). Initially, 5 mg/kg/day 17-α ethinylestradiol (EE) was used to induce cholestasis in rats and primary isolated rat hepatocytes. Subsequently, 9 or 36 g/kg/day YHHJ water extract was administrated. Blood samples were collected and serum biochemical parameters of total bile acids (TBA), total bilirubin (TBil), alanine transaminase and aspartate aminotransferase levels were determined. Rat livers and primary isolated rat hepatocytes were obtained and the protein and mRNA expression levels of MRP2 and BSEP were analyzed by western blot analysis and reverse transcription-quantitative polymerase chain reaction, respectively. Results revealed that EE-induced hepatocellular cholestasis was associated with a significant increase in serum TBA and TBil levels, whereas, YHHJ treatment significantly reversed this effect (P<0.01). Further experiments on the molecular mechanism revealed that EE significantly decreased the expression of MRP2 and BSEP compared with the control group, whereas YHHJ treatment significantly upregulated MRP2 and BSEP expression in vivo and in vitro compared with no YHHJ treatment (P<0.01). In addition, to establish whether upregulation of MRP2 and BSEP protein expression levels resulted from increased expression of their respective mRNA, the mRNA expression levels were determined. Results indicated that YHHJ treatment significantly increased MRP2 and BSEP mRNA expression levels in EE-induced hepatocellular cholestasis compared with no YHHJ treatment (P<0.01). In conclusion, the present findings suggest that YHHJ effects EE-induced cholestasis and this process may be mediated through regulating hepatobiliary transporters, MRP2 and BSEP.

Bile acids and gestation

There are numerous profound maternal physiological changes that occur from conception onwards and adapt throughout gestation in order to support a healthy pregnancy. By the time of late gestation, when circulating pregnancy hormones are at their highest concentrations, maternal adaptations include relative hyperlipidemia, hypercholanemia and insulin resistance. Bile acids have now been established as key regulators of metabolism, and their role in gestational changes in metabolism is becoming apparent. Bile acid homeostasis is tightly regulated by the nuclear receptor FXR, which has been shown to have reduced activity during pregnancy. This review focuses on the gestational alterations in bile acid homeostasis that occur in normal pregnancy, which in some women can become pathological, leading to the development of intrahepatic cholestasis of pregnancy. As well as their important role in maternal metabolic health, we will review bile acid metabolism in the feto-placental unit.

Role of AMP-activated protein kinase α1 in 17α-ethinylestradiol-induced cholestasis in rats

Estrogen-induced cholestasis occurs in many women who are susceptible due to pregnancy or hormone replacement therapy for postmenopausal syndrome. 17α-Ethinylestradiol (EE), as a synthetic estrogen, has been widely used to study the underlying mechanisms of estrogen-induced cholestasis. Recent studies have also reported that liver kinase B1 (LKB1)-mediated activation of AMP-activated protein kinase (AMPK) plays a critical role in the regulation of canalicular network formation. However, the role of AMPK in EE-induced cholestasis remains to be determined. In this study, the effects of EE (1-100 µM) on AMPK activation and the expression of farnesoid X receptor (FXR) and hepatic bile acid transporters were examined in in vitro using 3D-cultured rat primary hepatocytes and in in vivo using rat cholestasis models. We also used specific chemical agonist and antagonist of AMPK, AMPK subunit-specific antibodies and lentiviral shRNAs for AMPKα1 and AMPKα2 to delineate the role of AMPK in EE-induced cholestasis and potential cellular mechanisms. We found that EE-induced phosphorylation of AMPKα1 via extracellular signal-regulated kinases-LKB1-mediated signaling pathways and subsequent nuclear translocation accounted for the down-regulation of FXR and bile acid transporters and disruption of bile acid homeostasis. Inhibition of AMPK activation using an AMPK antagonist Compound C (2 µM) or down-regulation of AMPKα1 using gene-specific shRNA attenuated EE-induced cholestasis both in in vitro and in in vivo. In conclusion, these results revealed that activation of cAMP-ERK-LKB1-AMPKα1 signaling pathway plays a critical role in EE-mediated dysregulation of the expression of FXR and bile acid transporters. AMPKα1 may represent an important therapeutic target for estrogen-induced cholestasis.

Clinical application of transcriptional activators of bile salt transporters

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.

Intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disorder characterized by maternal pruritus in the third trimester, raised serum bile acids and increased rates of adverse fetal outcomes. The etiology of ICP is complex and not fully understood, but it is likely to result from the cholestatic effects of reproductive hormones and their metabolites in genetically susceptible women. Equally unclear are the mechanisms by which the fetal complications occur. This article reviews the epidemiology, clinical features, diagnosis, etiology and management of ICP.

Influence of Verapamil and Cyclosporin A on bile acid metabolism and transport in rat liver slices

Verapamil (V) is a specific inhibitor of the P-glycoprotein (mdr1) in the hepatocyte canalicular membrane. Cyclosporin A (CsA) as an essential immunosuppressive drug has potentially cholestatic adverse effects on the liver, but increases the expression of mdr1. In precision-cut liver slices from 34- to 40-day-old male Wistar rats 26 individual free and conjugated bile acids (BAs) as markers of hepatic transport and synthesis function were analysed after 4 h incubation with V (100 microM) or CsA (5 microM) in Krebs-Henseleit buffer. Some slices were loaded with cholic acid (CA 5 microM) or tauro-ursodeoxycholic acid (T-UDCA 5 microM) to investigate the V and CsA effects under conditions of BA supplementation. BAs were determined in tissue and medium by HPLC with postcolumn derivatisation and fluorescence detection. V and CsA, influencing different targets in BA transport, enhanced slice concentrations of T- and glyco- (G-) conjugated CA only when exogenous CA was given additionally. This BA accumulation in tissue is more reflected at decreased medium concentrations of these BAs after V and CsA incubations. Both V and CsA also inhibited CA uptake into the slices. The acidic chenodeoxycholic acid (CDCA) synthesis pathway is disturbed: T- and G-CDCA concentrations are diminished in slices and medium after V and CsA incubations. T-UDCA plus V or CsA enhanced not only its own slice concentration but also the concentration of the trihydroxylated tauro-muricholic acid (T-beta-MCA), reflecting the conversion of the accumulated dihydroxylated T-UDCA into the T-beta-MCA. The similar effects of V and CsA on BA transport and metabolism can be explained by mdr1 mediated disturbances of cellular ATP transport rather than by inhibition of individual BA transporters.

Bile acid transport and metabolism in rat liver slices

To further characterise precision-cut liver slices from 34- to 40-day-old male rats as an in vitro model for bile acid (BA) metabolism and transport, the effect of the primary BAs cholic (CA, 5 microM) and chenodeoxycholic acid (CDCA, 0.15 and 0.75 microM) as well as of the therapeutically used tauroursodeoxycholic acid (T-UDCA, 5 microM) on BA profiles was investigated. After 4 h incubation in 5 ml Krebs-Henseleit buffer (KHB) 26 individual BAs were determined in slices (50 mg liver/5 ml KHB) and medium by HPLC with postcolumn derivatisation and fluorescence detection. In control incubations, mean total BA concentrations were 5.09 nmol/50 mg liver (101.80 nmol/g liver) in slices and 25.71 nmol/5 ml KHB, among them 72% taurine-(T-), 22% glycine-(G-) conjugated and 6% free BAs in tissue and medium. The main BAs were beta-muricholic (beta-MCA and conjugates) and cholic acids (CA and conjugates) in tissue and medium. The following results were obtained after addition of CDCA, CA, and T-UDCA, respectively, to the KHB. The toxic CDCA was quantitatively converted mainly to T-UDCA and taurohyodeoxycholic (T-HDCA) acid. CA was conjugated in equal shares to T- and G-CA, whereas T-UDCA was enriched in slices and hydroxylated half to T-beta-MCA, which is the main BA in rats. In conclusion, rat liver slices are highly effective not only in uptake, conjugation and excretion of BAs but also in conversion of strong detergent into less toxic BAs.