Genome-wide characterization of circulating metabolic biomarkers

Genome-wide association analyses using high-throughput metabolomics platforms have led to novel insights into the biology of human metabolism1-7. This detailed knowledge of the genetic determinants of systemic metabolism has been pivotal for uncovering how genetic pathways influence biological mechanisms and complex diseases8-11. Here we present a genome-wide association study for 233 circulating metabolic traits quantified by nuclear magnetic resonance spectroscopy in up to 136,016 participants from 33 cohorts. We identify more than 400 independent loci and assign probable causal genes at two-thirds of these using manual curation of plausible biological candidates. We highlight the importance of sample and participant characteristics that can have significant effects on genetic associations. We use detailed metabolic profiling of lipoprotein- and lipid-associated variants to better characterize how known lipid loci and novel loci affect lipoprotein metabolism at a granular level. We demonstrate the translational utility of comprehensively phenotyped molecular data, characterizing the metabolic associations of intrahepatic cholestasis of pregnancy. Finally, we observe substantial genetic pleiotropy for multiple metabolic pathways and illustrate the importance of careful instrument selection in Mendelian randomization analysis, revealing a putative causal relationship between acetone and hypertension. Our publicly available results provide a foundational resource for the community to examine the role of metabolism across diverse diseases.

The role of ERp29/FOS/EMT pathway in excessive apoptosis of placental trophoblast cells in intrahepatic cholestasis of pregnancy

BACKGROUND

Abnormal bile acid metabolism leading to changes in placental function during pregnancy. To determine whether endoplasmic reticulum protein 29 (ERp29) can mediate the pregnancy effects of cholestasis by altering the level of trophoblast cell apoptosis.

METHODS

ERp29 in serum of 66 intrahepatic cholestasis of pregnancy (ICP) pregnant women and 74 healthy were detected by ELISA. Subcutaneous injection of ethinyl estradiol (E2) was used to induce ICP in pregnant rats. Taurocholic acid (TCA) was used to simulate the ICP environment, and TGF-β1 was added to induce the epithelial mesenchymal transformation (EMT) process. The scratch, migration, and invasion test were used to detect the EMT process. ERp29 overexpression/knockdown vector were constructed and transfected to verify the role of ERp29 in the EMT process. Downstream gene was obtained through RNA-seq.

RESULTS

Compared with the healthy pregnant women, the expression levels of ERp29 in serum of ICP pregnancy women were significantly increased (P < 0.001). ERp29 in the placenta tissue of the ICP pregnant rats increased significantly, and the level of apoptosis increased. The placental tissues of the ICP had high expression of E-cadherin and low expression of N-cadherin, snail1, vimentin. After HTR-8/SVneo cells were induced by TCA, EMT was inhibited, while the ERp29 increased. Cell and animal experiments showed that, knockdown of ERp29 reduced the inhibition of EMT, the ICP progress was alleviated. Overexpression of FOS salvaged the inhibitory effects of ERp29 on cell EMT.

DISCUSSION

The high level of ERp29 in placental trophoblast cells reduced FOS mRNA levels, inhibited the EMT process and aggravated the occurrence and development of ICP.

Clinical outcomes of ABCB4 heterozygosity in infants and children with cholestatic liver disease

OBJECTIVES

Biallelic variants in the adenosine triphosphate binding cassette subfamily B member 4 (ABCB4) gene which encodes the multidrug resistance 3 protein (MDR3) leads to progressive familiar intrahepatic cholestasis type 3. However, monoallelic variants are increasingly recognized as contributing to liver disease in adults. Our aim was to describe the clinical characteristics of MDR3 heterozygous variants in a large cohort of infants and children with cholestatic liver disease.

METHODS

The clinical and genotypic data on pediatric patients seen at King's College Hospital, London, between 2004 and 2022 and found to harbour heterozygous variants in ABCB4 were reviewed.

RESULTS

Ninety-two patients amongst 1568 tested were identified with a monoallelic variant (5.9%). The most common presenting problem was conjugated hyperbilirubinemia (n = 46; 50%) followed by cholelithiasis (n = 12; 13%) and cholestatic hepatitis (n = 10; 11%). The median values of liver biochemistry at presentation were: GGT 105 IU/L and total bilirubin 86 µmol/L. Thirty-two genetic variants were identified including 22 missense (69%), 4 deletions (13%), 5 splice site (16%) and 1 termination (3%). At a median follow up of 1 year there was resolution of liver disease.

CONCLUSIONS

Rare variants in ABCB4 were found amongst infants and children with cholestatic liver disease. The presenting problems were variable and abnormalities tended to normalize over time. Those with severe mutations could develop liver disease later in life when exposed to further insult and should be counseled appropriately.

Rare variant contribution to cholestatic liver disease in a South Asian population in the United Kingdom

This study assessed the contribution of five genes previously known to be involved in cholestatic liver disease in British Bangladeshi and Pakistani people. Five genes (ABCB4, ABCB11, ATP8B1, NR1H4, TJP2) were interrogated by exome sequencing data of 5236 volunteers. Included were non-synonymous or loss of function (LoF) variants with a minor allele frequency < 5%. Variants were filtered, and annotated to perform rare variant burden analysis, protein structure, and modelling analysis in-silico. Out of 314 non-synonymous variants, 180 fulfilled the inclusion criteria and were mostly heterozygous unless specified. 90 were novel and of those variants, 22 were considered likely pathogenic and 9 pathogenic. We identified variants in volunteers with gallstone disease (n = 31), intrahepatic cholestasis of pregnancy (ICP, n = 16), cholangiocarcinoma and cirrhosis (n = 2). Fourteen novel LoF variants were identified: 7 frameshift, 5 introduction of premature stop codon and 2 splice acceptor variants. The rare variant burden was significantly increased in ABCB11. Protein modelling demonstrated variants that appeared to likely cause significant structural alterations. This study highlights the significant genetic burden contributing to cholestatic liver disease. Novel likely pathogenic and pathogenic variants were identified addressing the underrepresentation of diverse ancestry groups in genomic research.

Serum Exosomes MicroRNAs Are Novel Non-Invasive Biomarkers of Intrahepatic Cholestasis of Pregnancy

Background

Intrahepatic cholestasis of pregnancy (ICP) is closely related to the occurrence of adverse outcomes. Currently, total bile acids (TBAs) are the only diagnostic index for ICP, and its sensitivity and specificity have certain limitations. In this study, we aimed to develop potential biomarkers for the diagnosis of ICP.

Methods

Sixty pregnant women diagnosed with ICP and 48 healthy pregnant controls were enrolled in this study. We used the Agilent microRNA (miRNA) array followed by quantitative reverse transcriptase polymerase chain reaction assays to identify and validate the serum exosome miRNA profiles in ICP and healthy pregnant controls. We employed bioinformatics to identify metabolic processes associated with differentially expressed serum exosome miRNAs.

Results

The expression levels of hsa-miR-4271, hsa-miR-1275, and hsa-miR-6891-5p in maternal serum exosomes were significantly lower in ICP patients compared to controls; the diagnostic accuracy of hsa-miR-4271, hsa-miR-1275, and hsa-miR-6891-5p was evaluated with the area under the receiver operating characteristic curve (AUC) values of 0.861, 0.886, and 0.838, respectively. Multiple logistic regression analysis showed that a combination of the levels of hsa-miR-4271and hsa-miR-1275 afforded a significantly higher AUC (0.982). The non-error rate of a combination of all three exosome miRNAs was the highest (95%), thus more reliable ICP diagnosis. The expression levels of all three exosome miRNAs were negatively associated with TBAs. Furthermore, according to bioinformatics analysis, the three exosome miRNAs were related to lipid metabolism, apoptosis, oxidative stress, and the Mitogen Activated Protein Kinase (MAPK) signaling pathway.

Conclusions

This study may identify the novel non-invasive biomarkers for ICP and provided new insights into the important role of the exosome miRNA regulation in ICP.

Liposome Extract of Stachys pilifera Benth Effectively Improved Liver Damage due to Bile Duct Ligation Rats

Herbal medicines harbor essential therapeutic agents for the treatment of cholestasis. In this study, we have assessed the anticholestatic potential of Stachys pilifera Benth's (SPB's) hydroalcoholic extract encapsulated into liposomes using bile duct ligation- (BDL-) induced hepatic cholestasis in rats. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), malondialdehyde (MDA), total thiol (T-SH) content, protein carbonyl (PCO), total bilirubin (TBIL), albumin (ALB), and nitric oxide (NO) metabolite levels were measured in either liver tissue or plasma to assess liver damage. Moreover, expression of proinflammatory cytokines (IL-1β and TNF-α) and liver fibrosis markers (TGF-β and SM-α) which are driving forces of many liver disorders was also determined. The activity of AST, ALT, and ALP was significantly enhanced in the BDL group in comparison to the control group; however, treatment with liposomal (SPB) hydroalcoholic extract significantly reduced AST and ALT's activity. Increases in MDA, TBIL, and NO levels and T-SH content due to BDL were restored to control levels by liposomal (SPB) hydroalcoholic extract treatment. Similarly, hepatic and plasma oxidative marker MDA levels, significantly enhanced by BDL, were significantly decreased by liposomal (SPB) hydroalcoholic extract treatment. Moreover, histopathological findings further demonstrated a significant decrease in hepatic damage in the liposomal (SPB) hydroalcoholic extract-treated BDL group. In addition, liposomal (SPB) hydroalcoholic extract treatment decreased the liver expression of inflammatory cytokines (IL-1β, TNF-α) and liver fibrosis markers (TGF-β and SM-α). Since liposomal (SPB) hydroalcoholic extract treatment alleviated the BDL-induced injury of the liver and improved the hepatic structure and function more efficiently in comparison to free SPB hydroalcoholic extract, probable liposomal (SPB) hydroalcoholic extract exhibits required potential therapeutic value in protecting the liver against BDL-caused oxidative injury.

Use of bile acids as potential markers of liver dysfunction in humans: A systematic review

OBJECTIVE

This study aimed to determine the effectiveness of using total, individual serum, or urinary bile acids (BA) as potential markers of liver dysfunction.

METHODS

We searched the PubMed and Web of Science databases using the following keywords- "serum bile acids," "liver dysfunction," "liver injury," "liver disease," "traditional liver function tests," "Chronic liver disease," "acute liver injury". The search was complemented by manual screening of the list of references for relevant articles. We selected only English-language manuscripts for adult patients based on predetermined inclusion and exclusion criteria. Animal studies and studies on neonates and children were not included.

OUTCOME MEASURES

Changes in BA concentrations or ratios at or prior to changes in liver function tests.

RESULTS

A total of 547 studies were identified, of which 28 were included after reading the entire manuscript. These studies included 1630 patients and 836 controls published between 1990 and 2017. The methods used in BA assays varied significantly, and the studies did not agree. on specific individual BA or BA ratios as biomarkers of specific liver injury or dysfunction. Except for the prognostic value of BA in intrahepatic cholestasis of pregnancy (ICP), studies have failed to provide evidence for BA as a liver biomarker.

CONCLUSIONS

Despite the research conducted on BA for over 27 years, there are inconsistencies in the reported results and a lack of solid evidence to support the use of individual BA or BA ratios as biomarkers of liver injury. Adequately conducted studies needed to resolve this limitation in the literature.

Placental Expression of Bile Acid Transporters in Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-related condition characterized by increased maternal circulating bile acids (BAs) having adverse fetal effects. We investigated whether the human placenta expresses specific regulation patterns to prevent fetal exposition to harmful amounts of BAs during ICP. Using real-time quantitative PCR, we screened placentae from healthy pregnancies (n = 12) and corresponding trophoblast cells (n = 3) for the expression of 21 solute carriers and ATP-binding cassette transporter proteins, all acknowledged as BA- and/or cholestasis-related genes. The placental gene expression pattern was compared between healthy women and ICP patients (n = 12 each). Placental SLCO3A1 (OATP3A1) gene expression was significantly altered in ICP compared with controls. The other 20 genes, including SLC10A2 (ASBT) and EPHX1 (EPOX, mEH) reported for the first time in trophoblasts, were comparably abundant in healthy and ICP placentae. ABCG5 was undetectable in all placentae. Placental SLC10A2 (ASBT), SLCO4A1 (OATP4A1), and ABCC2 mRNA levels were positively correlated with BA concentrations in ICP. Placental SLC10A2 (ASBT) mRNA was also correlated with maternal body mass index. We conclude that at the transcriptional level only a limited response of BA transport systems is found under ICP conditions. However, the extent of the transcriptional response may also depend on the severity of the ICP condition and the magnitude by which the maternal BA levels are increased.

Heme Oxygenase-1 Induction by Cobalt Protoporphyrin Ameliorates Cholestatic Liver Disease in a Xenobiotic-Induced Murine Model

Cholestatic liver diseases can progress to end-stage liver disease and reduce patients' quality of life. Although their underlying mechanisms are still incompletely elucidated, oxidative stress is considered to be a key contributor to these diseases. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme that displays antioxidant action. It has been found that this enzyme plays a protective role against various inflammatory diseases. However, the role of HO-1 in cholestatic liver diseases has not yet been investigated. Here, we examined whether pharmacological induction of HO-1 by cobalt protoporphyrin (CoPP) ameliorates cholestatic liver injury. To this end, a murine model of 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet feeding was used. Administration of CoPP ameliorated liver damage and cholestasis with HO-1 upregulation in DDC diet-fed mice. Induction of HO-1 by CoPP suppressed the DDC diet-induced oxidative stress and hepatocyte apoptosis. In addition, CoPP attenuated cytokine production and inflammatory cell infiltration. Furthermore, deposition of the extracellular matrix and expression of fibrosis-related genes after DDC feeding were also decreased by CoPP. HO-1 induction decreased the number of myofibroblasts and inhibited the transforming growth factor-β pathway. Altogether, these data suggest that the pharmacological induction of HO-1 ameliorates cholestatic liver disease by suppressing oxidative stress, hepatocyte apoptosis, and inflammation.

Dolomiaea souliei ethyl acetate extract protected against α-naphthylisothiocyanate-induced acute intrahepatic cholestasis through regulation of farnesoid x receptor-mediated bile acid metabolism

BACKGROUND

Cholestasis is characterized by accumulation of bile components in liver and systemic circulation. Restoration of bile acid homeostasis via activating farnesoid x receptor (FXR) is a promising strategy for the treatment of cholestasis. FXR-SHP (small heterodimer partner) axis plays an important role in maintaining bile acid homeostasis.

PURPOSE

To investigate the anti-cholestasis effect of Dolomiaea souliei (Franch.) C.Shih (D. souliei) and clarify its underlying mechanism against α-naphthylisothiocyanate (ANIT) induced acute intrahepatic cholestasis.

METHODS

ANIT-induced Sprague-Dawley rats were employed to investigate the anti-cholestasis effect of D. souliei ethyl acetate extract (DSE). Ursodeoxycholic acid (UDCA) was used as positive control. Bile flow and blood biochemical parameters were measured. Liver histopathological examination was conducted via hematoxylin-eosin staining. Western blot analysis was carried out to evaluate the protein levels related to bile acids metabolism and inflammation. The interactions between FXR and costunolide or dehydrocostus lactone, were conducted by molecular docking experiments. The effect of costunolide and dehydrocostus lactone on aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels and FXR expression were also evaluated using guggulsterone-induced L02 cells.

RESULTS

DSE could promote bile excretions and protect against ANIT-induced liver damage in cholestasis rats. Protein levels of FXR, SHP, Na+/taurocholate cotransporter (NTCP), bile salt export pump (BSEP), multidrug resistance-associated protein 2 (MRP2) were increased and the expressions of cholesterol 7α-hydroxylase (CYP7A1) and sterol 27-hydroxylase (CYP27A1) were decreased by DSE. Meanwhile, the anti-inflammatory factors, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) were also significantly increased, and the pro-inflammatory factor, interleukin-10 (IL-10), was significantly decreased in rats of DSE groups. Molecular docking revealed that costunolide and dehydrocostus lactone could be well docked into the FXR protein molecule, and hydrophobic interactions played the main function. Costunolide could reverse the increased AST and ALT levels and increase the FXR expression in guggulsterone-induced L02 cells.

CONCLUSION

DSE had an anti-cholestasis effect by activating FXR-SHP axis, inhibiting synthesis of bile acid, and increasing bile secretion, together with inflammatory response and improving liver injury. Costunolide may be the main active component. This study provided a potential therapeutic mechanism for D. souliei as an anti-cholestasis medicine in the treatment of cholestasis liver diseases.

Synthetic human ABCB4 mRNA therapy rescues severe liver disease phenotype in a BALB/c.Abcb4-/- mouse model of PFIC3

BACKGROUND & AIMS

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare lethal autosomal recessive liver disorder caused by loss-of-function variations of the ABCB4 gene, encoding a phosphatidylcholine transporter (ABCB4/MDR3). Currently, no effective treatment exists for PFIC3 outside of liver transplantation.

METHODS

We have produced and screened chemically and genetically modified mRNA variants encoding human ABCB4 (hABCB4 mRNA) encapsulated in lipid nanoparticles (LNPs). We examined their pharmacological effects in a cell-based model and in a new in vivo mouse model resembling human PFIC3 as a result of homozygous disruption of the Abcb4 gene in fibrosis-susceptible BALB/c.Abcb4-/- mice.

RESULTS

We show that treatment with liver-targeted hABCB4 mRNA resulted in de novo expression of functional hABCB4 protein and restored phospholipid transport in cultured cells and in PFIC3 mouse livers. Importantly, repeated injections of the hABCB4 mRNA effectively rescued the severe disease phenotype in young Abcb4-/- mice, with rapid and dramatic normalisation of all clinically relevant parameters such as inflammation, ductular reaction, and liver fibrosis. Synthetic mRNA therapy also promoted favourable hepatocyte-driven liver regeneration to restore normal homeostasis, including liver weight, body weight, liver enzymes, and portal vein blood pressure.

CONCLUSIONS

Our data provide strong preclinical proof-of-concept for hABCB4 mRNA therapy as a potential treatment option for patients with PFIC3.

LAY SUMMARY

This report describes the development of an innovative mRNA therapy as a potential treatment for PFIC3, a devastating rare paediatric liver disease with no treatment options except liver transplantation. We show that administration of our mRNA construct completely rescues severe liver disease in a genetic model of PFIC3 in mice.

Fibrotic Events in the Progression of Cholestatic Liver Disease

Cholestatic liver diseases including primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are associated with active hepatic fibrogenesis, which can ultimately lead to the development of cirrhosis. However, the exact relationship between the development of liver fibrosis and the progression of cholestatic liver disease remains elusive. Periductular fibroblasts located around the bile ducts seem biologically different from hepatic stellate cells (HSCs). The fibrotic events in these clinical conditions appear to be related to complex crosstalk between immune/inflammatory mechanisms, cytokine signalling, and perturbed homeostasis between cholangiocytes and mesenchymal cells. Several animal models including bile duct ligation (BDL) and the Mdr2-knockout mice have improved our understanding of mechanisms underlying chronic cholestasis. In the present review, we aim to elucidate the mechanisms of fibrosis in order to help to identify potential diagnostic and therapeutic targets.

Pharmacological Premature Termination Codon Readthrough of ABCB11 in Bile Salt Export Pump Deficiency: An In Vitro Study

BACKGROUND AND AIMS

Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a severe hepatocellular cholestasis due to biallelic mutations in ABCB11 encoding the canalicular bile salt export pump (BSEP). Nonsense mutations are responsible for the most severe phenotypes. The aim was to assess the ability of drugs to induce readthrough of six nonsense mutations (p.Y354X, p.R415X, p.R470X, p.R1057X, p.R1090X, and p.E1302X) identified in patients with PFIC2.

APPROACH AND RESULTS

The ability of G418, gentamicin, and PTC124 to induce readthrough was studied using a dual gene reporter system in NIH3T3 cells. The ability of gentamicin to induce readthrough and to lead to the expression of a full-length protein was studied in human embryonic kidney 293 (HEK293), HepG2, and Can 10 cells using immunodetection assays. The function of the gentamicin-induced full-length protein was studied by measuring the [³ H]-taurocholate transcellular transport in stable Madin-Darby canine kidney clones co-expressing Na+-taurocholate co-transporting polypeptide (Ntcp). Combinations of gentamicin and chaperone drugs (ursodeoxycholic acid, 4-phenylbutyrate [4-PB]) were investigated. In NIH3T3, aminoglycosides significantly increased the readthrough level of all mutations studied, while PTC124 only slightly increased the readthrough of p.E1302X. Gentamicin induced a readthrough of p.R415X, p.R470X, p.R1057X, and p.R1090X in HEK293 cells. The resulting full-length proteins localized within the cytoplasm, except for Bsep^R1090X , which was also detected at the plasma membrane of human embryonic kidney HEK293 and at the canalicular membrane of Can 10 and HepG2 cells. Additional treatment with 4-PB and ursodeoxycholic acid significantly increased the canalicular proportion of full-length Bsep^R1090X protein in Can 10 cells. In Madin-Darby canine kidney clones, gentamicin induced a 40% increase of the Bsep^R1090X [³ H]-taurocholate transport, which was further increased with additional 4-PB treatment.

CONCLUSION

This study constitutes a proof of concept for readthrough therapy in selected patients with PFIC2 with nonsense mutations.

ENDOCRINOLOGY IN PREGNANCY: Metabolic impact of bile acids in gestation

Bile acids are lipid-solubilising molecules that also regulate metabolic processes. Farnesoid X receptor (FXR) and Takeda G-protein coupled receptor 5 (TGR5) are two bile acid receptors with key metabolic roles. FXR regulates bile acid synthesis in the liver and influences bile acid uptake in the intestine. TGR5 is mainly involved in regulation of signalling pathways in response to bile acid uptake in the gut and therefore prandial response. Both FXR and TGR5 have potential as therapeutic targets for disorders of glucose and/or lipid homeostasis. Gestation is also known to cause small increases in bile acid concentrations, but physiological hypercholanaemia of pregnancy is usually not sufficient to cause any clinically relevant effects. This review focuses on how gestation alters bile acid homeostasis, which can become pathological if the elevation of maternal serum bile acids is more marked than physiological hypercholanaemia, and on the influence of FXR and TGR5 function in pregnancy on glucose and lipid metabolism. This will be discussed with reference to two gestational disorders: intrahepatic cholestasis of pregnancy (ICP), a disease where bile acids are pathologically elevated, and gestational diabetes mellitus (GDM), characterised by hyperglycaemia during pregnancy.

The Bile Salt Export Pump: Molecular Structure, Study Models and Small-Molecule Drugs for the Treatment of Inherited BSEP Deficiencies

The bile salt export pump (BSEP/ABCB11) is responsible for the transport of bile salts from hepatocytes into bile canaliculi. Malfunction of this transporter results in progressive familial intrahepatic cholestasis type 2 (PFIC2), benign recurrent intrahepatic cholestasis type 2 (BRIC2) and intrahepatic cholestasis of pregnancy (ICP). Over the past few years, several small molecular weight compounds have been identified, which hold the potential to treat these genetic diseases (chaperones and potentiators). As the treatment response is mutation-specific, genetic analysis of the patients and their families is required. Furthermore, some of the mutations are refractory to therapy, with the only remaining treatment option being liver transplantation. In this review, we will focus on the molecular structure of ABCB11, reported mutations involved in cholestasis and current treatment options for inherited BSEP deficiencies.

Dehydrodiconiferyl alcohol, a lignan from Herpetospermum pedunculosum, alleviates cholestasis by activating pathways associated with the farnesoid X receptor

BACKGROUND

In our previous study, we demonstrated the hepatoprotective effect of Herpetospermum pedunculosum in cholestatic rats. A bioassay-guided study also led to the identification and isolation of a lignan, dihydrodiconiferyl alcohol (DA) from the seeds of H. pedunculosum.

PURPOSE

To investigate whether DA could alleviate cholestasis and determine the mechanisms underlying such action.

METHODS

Male Sprague-Dawley (SD) rats were administered with DA (10, 20 or 40 mg/kg) intragastrically once daily for 7 days prior to treatment with α-naphthylisothiocyanate (ANIT) (60 mg/kg). We then evaluated the levels of a range of serum indicators, determined bile flow, and carried out histopathological analyses. Western blotting was then used to investigate the levels of inflammatory mediators and the Farnesoid X Receptor (FXR), proteins involved in the downstream biosynthesis of bile acids, and a range of transport proteins. Molecular docking was used to simulate the interaction between DA and FXR. Cell viability of human hepatocytes (L-02) cells was determined by MTT. Then, we treated guggulsterone-inhibited L-02 cells, Si-FXR L-02 cells, and FXR-overexpression cells with the FXR agonist GW4064 (6 μM) or DA (25, 50 and 100 μM) for 24 h before detecting gene and protein expression by RT-PCR and western blotting, respectively.

RESULTS

DA significantly attenuated ANIT-induced cholestasis in SD rats by reducing liver function indicators in the serum, increasing bile flow, improving the recovery of histopathological injuries in the liver, and by alleviating pro-inflammatory cytokines in the liver. DA also increased the expression levels of FXR and altered the levels of downstream proteins in the liver tissues, thus indicating that DA might alleviate cholestasis by regulating the FXR. Molecular docking simulations predicted that DA was as an agonist of FXR. In vitro mechanical studies further showed that DA increased the mRNA and protein expression levels of FXR, Small Heterodimer Partner 1/2, Bile Salt Export Pump, Multidrug Resistance-associated Protein 2, and Na+/taurocholate Co-transporting Polypeptide, in both guggulsterone-inhibited and Si-FXR L-02 cells. Moreover, DA enhanced the mRNA and protein expression of FXR, and its downstream genes and proteins, in L-02 cells containing an FXR-overexpression plasmid.

CONCLUSION

DA may represent an effective agonist for FXR has significant therapeutic potential for the treatment of cholestatic liver injury.

Maternal glucose homeostasis is impaired in mouse models of gestational cholestasis

Women with intrahepatic cholestasis of pregnancy (ICP), a disorder characterised by raised serum bile acids, are at increased risk of developing gestational diabetes mellitus and have impaired glucose tolerance whilst cholestatic. FXR and TGR5 are modulators of glucose metabolism, and FXR activity is reduced in normal pregnancy, and further in ICP. We aimed to investigate the role of raised serum bile acids, FXR and TGR5 in gestational glucose metabolism using mouse models. Cholic acid feeding resulted in reduced pancreatic β-cell proliferation and increased apoptosis in pregnancy, without altering insulin sensitivity, suggesting that raised bile acids affect β-cell mass but are insufficient to impair glucose tolerance. Conversely, pregnant Fxr-/- and Tgr5-/- mice are glucose intolerant and have reduced insulin secretion in response to glucose challenge, and Fxr-/- mice are also insulin resistant. Furthermore, fecal bile acids are reduced in pregnant Fxr-/- mice. Lithocholic acid and deoxycholic acid, the principal ligands for TGR5, are decreased in particular. Therefore, we propose that raised serum bile acids and reduced FXR and TGR5 activity contribute to the altered glucose metabolism observed in ICP.

If It Looks Like a Duct and Acts Like a Duct: On the Role of Reprogrammed Hepatocytes in Cholangiopathies

Cholangiopathies are chronic, progressive diseases of the biliary tree, and can be either acquired or genetic. The primary target is the cholangiocyte (CC), the cell type lining the bile duct that is responsible for bile modification and transport. Despite advances in our understanding and diagnosis of these diseases in recent years, there are no proven therapeutic treatments for the majority of the cholangiopathies, and liver transplantation is the only life-extending treatment option for patients with end-stage cholestatic liver disease. One potential therapeutic strategy is to facilitate endogenous repair of the biliary system, which may alleviate intrahepatic cholestasis caused by these diseases. During biliary injury, hepatocytes (HC) are known to alter their phenotype and acquire CC-like features, a process known as cellular reprogramming. This brief review discusses the potential ways in which reprogrammed HC may contribute to biliary repair, thereby restoring bile flow and reducing the severity of cholangiopathies. Some of these include modifying bile to reduce toxicity, serving as a source of de novo CC to repair the biliary epithelium, or creating new channels to facilitate bile flow.

Yinchenzhufu decoction protects against alpha-naphthylisothiocyanate-induced acute cholestatic liver injury in mice by ameliorating disordered bile acid homeostasis and inhibiting inflammatory responses

ETHNOPHARMACOLOGICAL RELEVANCE

Intrahepatic cholestasis is a common condition of many liver diseases with few therapies. Yinchenzhufu decoction (YCZFD) is a representative traditional Chinese herbal formula used for treating jaundice and liver disease.

AIM OF THE STUDY

To investigate the hepatoprotective effect of YCZFD against cholestatic liver injury and reveal its potential mechanism.

MATERIALS AND METHODS

Mice with alpha-naphthyl isothiocyanate (ANIT)-induced intrahepatic cholestasis were orally administered YCZFD at doses of 3, 6, and 12g crude drug/kg for 2 weeks followed by subsequent analyses. A serum metabolomics study was then performed to explore the different metabolites influenced by YCZFD using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap hybrid mass spectrometry (UPLC-LTQ-Orbitrap-MS/MS).The levels of individual bile acids in the serum, liver, and bile were determined by UPLC-MS/MS. The expression of metabolic enzymes, transporters, inflammatory factors, and cytokeratin-19 (CK-19) was determined by real-time PCR, western blotting, and immunohistochemistry.

RESULTS

YCZFD administration decreased the serum biochemical indexes and ameliorated pathological damage, such as hepatic necrosis and inflammatory cell infiltration. Serum metabolomics revealed that the metabolites influenced by YCZFD were mainly associated with bile acid metabolism and inflammation. YCZFD administration effectively ameliorated the disordered bile acid homeostasis. The bile acid transporter, multidrug-resistance associated protein 2 (Mrp2), and the metabolic enzyme, cytochrome P450 2b10 (Cyp2b10), were upregulated in the YCZFD intervention group compared to those in the ANIT-induced group. YCZFD administration also significantly inhibited nuclear factor-κB (NF-κB) and its phosphorylation and decreased the expression of proinflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and intercellular adhesion molecule-1 in ANIT-induced cholestatic mice. Additionally, the level of CK-19 was lower in the YCZFD intervention group than in the ANIT-induced cholestatic mice.

CONCLUSION

YCZFD administration ameliorated disordered bile acid homeostasis, inhibited NF-κB pathway-mediated inflammation, and protected the liver from bile duct injury. Therefore, YCZFD exerted a protective effect against cholestatic liver injury.

LCAT protects against Lipoprotein-X formation in a murine model of drug-induced intrahepatic cholestasis

Familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD) is a rare genetic disease characterized by low HDL-C levels, low plasma cholesterol esterification, and the formation of Lipoprotein-X (Lp-X), an abnormal cholesterol-rich lipoprotein particle. LCAT deficiency causes corneal opacities, normochromic normocytic anemia, and progressive renal disease due to Lp-X deposition in the glomeruli. Recombinant LCAT is being investigated as a potential therapy for this disorder. Several hepatic disorders, namely primary biliary cirrhosis, primary sclerosing cholangitis, cholestatic liver disease, and chronic alcoholism also develop Lp-X, which may contribute to the complications of these disorders. We aimed to test the hypothesis that an increase in plasma LCAT could prevent the formation of Lp-X in other diseases besides FLD. We generated a murine model of intrahepatic cholestasis in LCAT-deficient (KO), wild type (WT), and LCAT-transgenic (Tg) mice by gavaging mice with alpha-naphthylisothiocyanate (ANIT), a drug well known to induce intrahepatic cholestasis. Three days after the treatment, all mice developed hyperbilirubinemia and elevated liver function markers (ALT, AST, Alkaline Phosphatase). The presence of high levels of LCAT in the LCAT-Tg mice, however, prevented the formation of Lp-X and other plasma lipid abnormalities in WT and LCAT-KO mice. In addition, we demonstrated that multiple injections of recombinant human LCAT can prevent significant accumulation of Lp-X after ANIT treatment in WT mice. In summary, LCAT can protect against the formation of Lp-X in a murine model of cholestasis and thus recombinant LCAT could be a potential therapy to prevent the formation of Lp-X in other diseases besides FLD.

ERp29 inhibition attenuates TCA toxicity via affecting p38/p53- dependent pathway in human trophoblast HTR-8/SVeno cells

Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder occurred in pregnant women, and the mechanism for such disease is still unclear. The bioinformatics analysis of our previous study has revealed the abnormal expression of endoplasmic reticulum protein 29 (ERp29) in placental tissue of ICP patients. In this study, the function of ERp29 was further explored using in vitro model of ICP. The results showed that up-regulation of ERp29 occurred in TCA (taurocholic acid)-treated human trophoblast HTR-8/SVeno cells, and ERp29 inhibition reversed TCA toxicity via attenuating G2/M arrest and cell apoptosis. Mechanical study revealed ERp29 inhibition suppressed phosphorylation and kinase activity of p38, thus subsequently affecting expression and phosphorylation of p53 (ser18) as well as the transcriptional activity of p53. The conduction of this study might confirm the important role of ERp29 in ICP and which would be helpful for the development of target therapeutic method for ICP.

Protective effect of herbal medicine Huangqi decoction against chronic cholestatic liver injury by inhibiting bile acid-stimulated inflammation in DDC-induced mice

BACKGROUND

Huangqi decoction (HQD), a classic traditional herbal medicine, has been used for liver fibrosis, but its effect on intrahepatic chronic cholestatic liver injury remains unknown.

PURPOSE

In the present study, we investigated the hepatoprotective effect of HQD and the underlying molecular mechanisms in 3, 5-diethoxycarbonyl-1, 4-dihydroxychollidine (DDC)-induced chronic cholestatic mice.

METHODS

The DDC-induced cholestatic mice were administrated HQD for 4 or 8 weeks. Serum biochemistry and morphology were investigated. The serum and liver bile acid (BA) levels were detected by ultra performance liquid chromatography-tandem mass spectrometry. The liver expression of BA metabolizing enzymes and transporters, and inflammatory and fibrotic markers was measured by real-time polymerase chain reaction, western blotting, and immunohistochemistry.

RESULTS

HQD treatment for 4 or 8 weeks ameliorated DDC-induced liver injury by improving impaired hepatic function and tissue damage. HQD treatment for 8 weeks further decreased the liver expression of cytokeratin 19, tumor growth factor (TGF)-β, collagen I, and α-smooth muscle actin, and ameliorated ductular reaction and liver fibrosis. HQD markedly decreased the accumulation of serum and liver BA. The expression of BA-metabolizing enzymes, cytochrome P450 2b10 and UDP glucuronosyltransferase 1 A1, and multidrug resistance-associated protein 2, Mrp3, and Mrp4 involved in BA homeostasis was increased by 4 weeks of HQD treatment. The expression of BA uptake transporter Na⁺-taurocholate cotransporting polypeptide was decreased and that of Mrp4 was increased after 8 weeks of HQD treatment. Nuclear factor-E2-related factor-2 (Nrf2) was remarkably induced by HQD treatment. Additionally, HQD treatment for 8 weeks decreased the liver expression of inflammatory factors, interleukin (IL)-6, IL-1β, tumor necrosis factor-α, monocyte chemoattractant protein-1, and intracellular adhesion molecule-1. HQD suppressed the nuclear factor (NF)-κB pathway.

CONCLUSION

HQD protected mice against chronic cholestatic liver injury and biliary fibrosis, which may be associated with the induction of the Nrf2 pathway and inhibition of the NF-κB pathway, ameliorating BA-stimulated inflammation.

The Impact of a Nitric Oxide Synthase Inhibitor (L-NAME) on Ischemia⁻Reperfusion Injury of Cholestatic Livers by Pringle Maneuver and Liver Resection after Bile Duct Ligation in Rats

The Pringle maneuver (PM) has been widely used to control blood loss during liver resection. However, hepatic inflow occlusion can also result in hepatic ischemia–reperfusion injury (IRI), especially in patients with a cholestatic, fibrotic, or cirrhotic liver. Here we investigate a nitric oxide synthase (NOS) inhibitor N-Nitroarginine methyl ester (L-NAME) on IRI after the PM and partial hepatectomy of cholestatic livers induced by bile duct ligation (BDL) in rats. Control group (non-BDL/no treatment), BDL + T group (BDL/L-NAME treatment) and BDL group (BDL/no treatment) were analyzed. Cholestasis was induced by BDL in the L-NAME and BDL group and a 50% partial hepatectomy with PM was performed. L-NAME was injected before PM in the BDL + T group. Hepatocellular damage, portal venous flow, microcirculation, endothelial lining, and eNOS, iNOS, interleukin (IL)-6, and transforming growth factor-β (TGF-β) were evaluated. Microcirculation of the liver in the BDL + T group tended to be higher. Liver damage and apoptotic index were significantly lower and Ki-67 labeling index was higher in the BDL + T group while iNOS and TGF-β expression was decreased. This was corroborated by a better preserved endothelial lining. L-NAME attenuated IRI following PM and improved proliferation/regeneration of cholestatic livers. These positive effects were considered as the result of improved hepatic microcirculation, prevention of iNOS formation, and TGF-β mRNA upregulation.

Hepatoprotective potential of standardized Ficus species in intrahepatic cholestasis rat model: Involvement of nuclear factor-κB, and Farnesoid X receptor signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Ficus is an important commercial crop not only for its nutritive value but also, for its medicinal value. Several Ficus species have been traditionally used in the Egypt, Indian and Chinese as carminative, astringent, antibacterial, hepatoprotective, and hypolipidemic agents.

AIM OF THE STUDY

To standardize and compare the possible hepatoprotective potential of the ethanolic extract of leaves of five tested Ficus species namely: Ficus mysorensis Roth ex Roem. & Schult, Ficus pyriformis Hook. & Arn., Ficus auriculata Lour., Ficus trigonata L., and Ficus spragueana Mildbr. & Burret in the intrahepatic cholestasis rat model induced by 17α-Ethinylestradiol (EE) and to explore the mechanism of action with respect to their phytochemical constituents.

MATERIALS AND METHODS

Determination of the total phenolic and flavonoid contents, chromatographic examination and acute oral toxicity test were performed on the tested Ficus extracts. Animals were divided into 8 groups. Group 1, served as control for 2 weeks. Group 2, untreated cholestatic rats. Groups 3-8, pretreated with Ficus extracts (100 mg/Kg/day, p.o) or ursodeoxycholic acid (as reference drug) for 2 weeks and injected by EE in the last 5 days. Serum liver function test, 5'-nucleotidase (5'-N), total bile acids (TBA), total cholesterol (T.C) and phospholipids were assayed. Also, hepatic Na⁺/K⁺-ATPase, nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), hepatocyte growth factor (HGF), hemeoxygenase-1 (HO-1), and markers of oxidative stress were investigated. Furthermore, molecular docking study was performed to explore the ability of the major constituents of Ficus to interact with Farnesoid X receptor (FXR).

RESULTS

Four phenolic compounds (gallic, chlorogenic acid, caffeic acids and rutin) were identified. Chlorogenic acid and rutin represented the major constituents of Ficus extracts. Simultaneous administration of Ficus extracts with EE effectively: i- preserved liver function, TBA, T.C and phospholipids, ii- suppressed the pro-inflammatory cytokines (NF-κB and TNF-α), iii- enhanced hepatic regeneration (HGF) and antioxidant defense system. Furthermore, molecular docking reveals that rutin and chlorogenic acid effectively act as FXR agonists.

CONCLUSION

Among the tested extracts, Ficus spragueana Mildbr. & Burret enriched with phenolics exhibited a pronounced hepatoprotective activity and may provide a new therapeutic approach for estrogen-induced cholestasis.

[A case of congenital bile acid synthesis disorder type 2 and literature review]

OBJECTIVE

To summarize the clinical features, biochemical change and genetic mutations of a neonate with congenital bile acid synthesis disorder type 2.

METHODS

Clinical features, blood biochemical index, gene analysis and treatment of the patient were reviewed.

RESULTS

The patient presented with the symptoms of jaundice 3 days after birth but without skin itching. Pale stool was noted. Subsequently, he presented with hepatomegaly, blood coagulation disorders, left cochlear nerve damage, liver cirrhosis and remarkable growth retardation. Serum biochemistries showed that bilirubin and transaminase were elevated, while γ -GT and total bile acid was normal. Abdominal ultrasonography indicated decline of gallbladder contraction. Cholangiography showed normal extra- and intrahepatic bile ducts and patent biliary tract. Liver biopsy showed intrahepatic cholestasis. Gene testing has identified a homozygous mutation in AKR1D1 gene.

CONCLUSION

Congenital bile acid synthesis disorder should be suspected when a neonate has presented with jaundice, elevated bilirubin and transaminase, normal or reduced TBA and γ -GT. Genetic testing and urine mass spectrometry analysis can diagnose congenital bile acid synthesis disorder. Early therapy is crucial to patients with congenital bile acid synthesis disorder.

Metabolomic profiling of maternal hair suggests rapid development of intrahepatic cholestasis of pregnancy

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) is a common maternal liver disease; development can result in devastating consequences, including sudden fetal death and stillbirth. Currently, recognition of ICP only occurs following onset of clinical symptoms.

OBJECTIVE

Investigate the maternal hair metabolome for predictive biomarkers of ICP.

METHODS

The maternal hair metabolome (gestational age of sampling between 17 and 41 weeks) of 38 Chinese women with ICP and 46 pregnant controls was analysed using gas chromatography-mass spectrometry.

RESULTS

Of 105 metabolites detected in hair, none were significantly associated with ICP.

CONCLUSION

Hair samples represent accumulative environmental exposure over time. Samples collected at the onset of ICP did not reveal any metabolic shifts, suggesting rapid development of the disease.

[Role of endoplasmic reticulum stress-induced apoptosis of trophoblasts in intrahepatic cholestasis during pregnancy]

OBJECTIVE

To investigate the role of endoplasmic reticulum stress (ERS)-induced trophoblast apoptosis in the development of intrahepatic cholestasis during pregnancy (ICP).

METHODS

Twenty pregnant women with ICP and 20 normal pregnant women undergoing cesarean section were enrolled in this study. The number of placenta syncytial knots in these women was determined using HE staining. The mRNA expressions of GRP78, CHOP, caspase-3, and caspase-7 were detected using RT-PCR in the placental tissues of the women and also in HTR-8/SVneo cells treated with different doses of deoxycholic acid (DCA). Caspase-3 and caspase-7 activities were also detected in DCA-treated HTR-8/SVneo cells using commercial assay kits, and the presence of apoptotic bodies in the cells were detected with electron microscopy.

RESULTS

Compared with normal placental tissues, the placenta from women with ICP showed significantly increased syncytial knots (P<0.01) and obviously enhanced mRNA expressions of GRP78, CHOP, caspase-3, and caspase-7 (P<0.05). In HTR-8/SVneo cells treated with different doses of DCA (0, 10, 50, and 100 µmol/L), the mRNA expressions of GRP78, CHOP, caspase-3 and caspase-7 were significantly increased in a dose-dependent manner (P<0.05) and the protein levels of GRP78 and CHOP were also increased dose-dependently. Treatment with DCA at 50 µmol/L for 24 h significantly upregulated caspase-3 and caspase-7 activity in the cells (P<0.05), and the cells treated with 50 µmol/L DCA for 12 h showed the presence of apoptotic bodies.

CONCLUSION

The activation of ERS and enhanced apoptosis of the trophoblasts occur in the placenta of women with ICP. DCA can significantly increase the expressions of ERS markers and thus lead to trophoblast apoptosis, suggesting that ERS-induced trophoblasts apoptosis may play a key role in the development of ICP.

[Role of endoplasmic reticulum stress-induced apoptosis of trophoblasts in intrahepatic cholestasis during pregnancy]

OBJECTIVE

To investigate the role of endoplasmic reticulum stress (ERS)-induced trophoblast apoptosis in the development of intrahepatic cholestasis during pregnancy (ICP).

METHODS

Twenty pregnant women with ICP and 20 normal pregnant women undergoing cesarean section were enrolled in this study. The number of placenta syncytial knots in these women was determined using HE staining. The mRNA expressions of GRP78, CHOP, caspase-3, and caspase-7 were detected using RT-PCR in the placental tissues of the women and also in HTR-8/SVneo cells treated with different doses of deoxycholic acid (DCA). Caspase-3 and caspase-7 activities were also detected in DCA-treated HTR-8/SVneo cells using commercial assay kits, and the presence of apoptotic bodies in the cells were detected with electron microscopy.

RESULTS

Compared with normal placental tissues, the placenta from women with ICP showed significantly increased syncytial knots (P<0.01) and obviously enhanced mRNA expressions of GRP78, CHOP, caspase-3, and caspase-7 (P<0.05). In HTR-8/SVneo cells treated with different doses of DCA (0, 10, 50, and 100 µmol/L), the mRNA expressions of GRP78, CHOP, caspase-3 and caspase-7 were significantly increased in a dose-dependent manner (P<0.05) and the protein levels of GRP78 and CHOP were also increased dose-dependently. Treatment with DCA at 50 µmol/L for 24 h significantly upregulated caspase-3 and caspase-7 activity in the cells (P<0.05), and the cells treated with 50 µmol/L DCA for 12 h showed the presence of apoptotic bodies.

CONCLUSION

The activation of ERS and enhanced apoptosis of the trophoblasts occur in the placenta of women with ICP. DCA can significantly increase the expressions of ERS markers and thus lead to trophoblast apoptosis, suggesting that ERS-induced trophoblasts apoptosis may play a key role in the development of ICP.

Cholestatic Liver Disease with Ductopenia (Vanishing Bile Duct Syndrome) in Hodgkin's Disease: Report of a Case

Liver involvement is common in advanced stages of Hodgkin's disease. However, only a small percentage of patients with Hodgkin's disease develops jaundice due to several causes. Vanishing bile duct syndrome secondary to Hodgkin's disease is a rare cause of cholestasis in these patients. Only 20, cases, to our knowledge, have been reported so far in adults. We report a case of Hodgkin's disease presenting with obstructive jaundice without detectable liver involvement. Liver biopsies revealed intrahepatic cholestasis and ductopenia. Although the patient was given chemotherapy, he died of sepsis and disseminated intravascular coagulation after 24 weeks of admission to hospital.

Effect of intrahepatic cholestasis of pregnancy on maternal serum screening tests

OBJECTIVE

In this study, we aimed to evaluate whether the changes in the first and second trimester maternal serum biochemical markers used for prenatal screening are associated with euploid pregnancies complicated by intrahepatic cholestasis of pregnancy (ICP).

METHODS

A total of 94 pregnant women were included in this retrospective comparative study. Thirty-seven women whose pregnancy was complicated with ICP constituted the study group whereas 57 of them constituted the control group. All hospital records were examined in terms of combined first trimester screening test and second trimester triple test parameters. Perinatal outcomes were also recorded.

RESULTS

No significant difference was observed between the two groups in term of age, BMI, and obstetric history (all p > 0.05). Mean serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and serum bile acid concentrations in the study group were significantly higher than in the controls (p < 0.001). There were no significant differences between the two groups in terms of first and second trimester serum biochemical markers. Newborn gender, route of birth, and NICU admission rates were also similar in the two groups. Mean birth weight of the control group was statistically significantly higher than the ICP group (p = 0.012).

CONCLUSION

We report no significant differences between pregnancies complicated by ICP and healthy pregnancies in terms of first and second trimester maternal serum screening test results.

Effects of andrographolide on intrahepatic cholestasis induced by alpha-naphthylisothiocyanate in rats

Cholestasis is a cardinal manifestation of liver diseases but effective therapeutic approaches are limited. Therefore, alternative therapy for treating and preventing cholestatic liver diseases is necessary. Andrographolide, a promising anticancer drug derived from the medicinal plant Andrographis paniculata, has diverse pharmacological properties and multi-spectrum therapeutic applications. However, it is unknown whether andrographolide has a hepatoprotective effect on intrahepatic cholestasis. The aims of this study were to investigate the protective effect and possible mechanisms of andrographolide in a rat model of acute intrahepatic cholestasis induced by alpha-naphthylisothiocyanate (ANIT). Andrographolide was administered intragastrically for four consecutive days, with a single intraperitoneal injection of ANIT on the second day. Liver injury was evaluated biochemically and histologically together with hepatic gene and protein expression analysis. Rats pretreated with andrographolide prior to ANIT injection demonstrated lower levels of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyltransferase, as well as bilirubin and bile acids as compared to rats treated with ANIT alone. Andrographolide also decreased the incidence and extent of periductular fibrosis and bile duct proliferation. Analysis of protein expression in livers from andrographolide-treated cholestatic rats revealed markedly decreased expression of alpha-smooth muscle actin and nuclear factor kappa-B (NF-κB). In conclusion, andrographolide has a potent protective property against ANIT-induced cholestatic liver injury. The mechanisms that underlie this protective effect are mediated through down-regulation of NF-κB expression and inhibition of hepatic stellate cell activation. These findings suggest that andrographolide could be a promising therapeutic option in prevention and slowing down the progression of cholestatic liver diseases.

A Comprehensive Evaluation of Steroid Metabolism in Women with Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a common liver disorder, mostly occurring in the third trimester. ICP is defined as an elevation of serum bile acids, typically accompanied by pruritus and elevated activities of liver aminotransferases. ICP is caused by impaired biliary lipid secretion, in which endogenous steroids may play a key role. Although ICP is benign for the pregnant woman, it may be harmful for the fetus. We evaluated the differences between maternal circulating steroids measured by RIA (17-hydroxypregnenolone and its sulfate, 17-hydroxyprogesterone, and cortisol) and GC-MS (additional steroids), hepatic aminotransferases and bilirubin in women with ICP (n = 15, total bile acids (TBA) >8 μM) and corresponding controls (n = 17). An age-adjusted linear model, receiver-operating characteristics (ROC), and multivariate regression (a method of orthogonal projections to latent structure, OPLS) were used for data evaluation. While aminotransferases, conjugates of pregnanediols, 17-hydroxypregnenolone and 5β-androstane-3α,17β-diol were higher in ICP patients, 20α-dihydropregnenolone, 16α-hydroxy-steroids, sulfated 17-oxo-C19-steroids, and 5β-reduced steroids were lower. The OPLS model including steroids measured by GC-MS and RIA showed 93.3% sensitivity and 100% specificity, while the model including steroids measured by GC-MS in a single sample aliquot showed 93.3% sensitivity and 94.1% specificity. A composite index including ratios of sulfated 3α/β-hydroxy-5α/β-androstane-17-ones to conjugated 5α/β-pregnane-3α/β, 20α-diols discriminated with 93.3% specificity and 81.3% sensitivity (ROC analysis). These new data demonstrating altered steroidogenesis in ICP patients offer more detailed pathophysiological insights into the role of steroids in the development of ICP.

Hepatic immunohistochemistry of bile transporters in progressive familial intrahepatic cholestasis

 Background. Diagnosis of progressive familial intrahepatic cholestasis (PFIC) is a challenging matter that involves the summation of clinical, laboratory, radiological, and liver histological parameters; in addition to specific investigations to exclude other causes of neonatal cholestasis. The aim of this study was to evaluate liver tissue immunohistochemistry of bile salt export pump (BSEP) and multidrug resistance 3 (MDR3) proteins in differentiating PFIC from other causes of neonatal cholestasis, particularly, when genotyping is unavailable.

MATERIAL AND METHODS

The study included 25 patients diagnosed phenotypically as PFIC including 2 with PFIC1, 17 with PFIC2 and 6 with PFIC3. A second group of 25 cholestatic newborns with confirmed etiologies other than PFIC, termed as non-PFIC, included as controls. Liver biopsies from all patients were obtained and immunostained for BSEP and MDR3.

RESULTS

Negative immunoreaction of BSEP and MDR3 was found in the majority of PFIC group (76 and 64% respectively). Nonetheless, the negative immunoreaction was demonstrated in a considerable number of the non-PFIC group. BSEP immunoreaction was negative in the majority (82.4%) of PFIC2 but in none of the two patients with PFIC1. In addition, negative MDR3 immunoreaction was more frequently associated with PFIC3 compared to non-PFIC group.

CONCLUSION

MDR3 and BSEP immunostaining would be a helpful tool in supporting the phenotypic diagnosis of PFIC subtypes and in differentiating PFIC from other causes of neonatal cholestasis.

[Protective effect of emodin pretreatment in young rats with intrahepatic cholestasis]

OBJECTIVE

To investigate the protective effect of emodin in young rats with intrahepatic cholestasis.

METHODS

A total of 120 young Sprague-Dawley rats were randomly divided into control, model, and high-, medium-, and low-dose emodin groups, with 24 rats in each group. The rats in the control and model groups were given sodium carboxymethyl cellulose solution by gavage, while the other groups were given different doses of emodin solution by gavage. On the 5th day of experiment, alpha-naphthylisothiocyanate (ANIT, 50 mg/kg) was applied by gavage to establish the model of intrahepatic cholestasis in all groups except the control group. At 24, 48, and 72 hours after gavage, 8 rats in each group were sacrificed. Colorimetry was used to measure the serum levels of total bilirubin (TBIL), direct bilirubin (DBIL), total bile acid (TBA), alkaline phosphatase (ALP), gamma glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in each group, and hematoxylin-eosin staining was applied to observe the morphological changes of the liver under a light microscope at different time points.

RESULTS

Compared with the control group, the model group had significantly increased serum levels of TBIL, DBIL, TBA, ALP, GGT, ALT, and AST at the 24-hour, 48-hour, and 72-hour time points (P<0.01). In the model group, the serum levels of TBIL, DBIL, TBA, ALT, and AST showed varying degrees of increase at 48 hours after establishment of model, compared with the values at 24 and 72 hours (P<0.05). At 24, 48, and 72 hours, the high-, medium-, and low-dose emodin groups had varying degrees of reductions in the serum levels of TBIL and TBA compared with the model group (P<0.05); the high- and low-dose emodin groups had significantly increased serum levels of TBA compared with the medium-dose emodin group (P<0.05). The model group had the most severe pathological changes at 48 hours. Compared with the model group, the high-, medium-, and low-dose emodin groups showed certain improvement in pathological changes of the liver at each time point, and the medium-dose emodin group had better improvement compared with the high- and low-dose emodin groups.

CONCLUSIONS

Emodin can effectively improve ANIT-induced intrahepatic cholestasis in young rats, and medium-dose emodin shows the best effect.

Expression of vascular endothelial growth factor (VEGF) under hypoxia in placenta with intrahepatic cholestasis of pregnancy and its clinically pathological significance

The expression of vascular endothelial growth factor (VEGF) under hypoxia in the placenta with intrahepatic cholestasis of pregnancy (ICP) was observed, and mechanisms of ICP fetal distress were discussed.

METHODS

Different culturing times were established in hypoxia incubator, and protein expressions of VEGF in placental tissue were observed using immunohistochemical S-P method.

RESULTS

After 4 h hypoxic culture, VEGF protein expression in ICP group was higher than the normal group with significant difference (P < 0.05). With the extension of hypoxic exposure, VEGF protein expression in both groups was suppressed, but no distinction in-between. Regression analyses indicated a noticeable effect of CG on VEGF expression, the higher the CG was, the lower the VEGF protein expression was (P < 0.05).

CONCLUSIONS

Short term hypoxia induces up-regulation of VEGF expression in ICP placenta, and this adaptive change is probably a protective mechanism of fetus in ICP.

Oxidative stress markers in intrahepatic cholestasis of pregnancy: a prospective controlled study

OBJECTIVE

Intrahepatic cholestasis of pregnancy (ICP), characterized by skin pruritus and elevation of serum aminotransferase activity and bile acid concentration in the mother, is one of the most common liver disorders in pregnancy. It was proved that ICP might lead to fetal distress by triggering oxidative damage. Total bile acids (TBA) are an established marker for assessment of the severity of ICP. The aim of this study was to explore associations of TBA levels with levels of the oxidative stress markers 8-epimer of prostaglandin F2alpha (8-iso-PGF2α), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) in ICP.

PATIENTS AND METHODS

Maternal plasma levels of 8-iso-PGF2α, SOD and Gpx were examined in ICP patients (n=40) and normal pregnancy controls (n=47) using an enzyme-linked immunosorbent assay (ELISA) analysis.

RESULTS

Plasma levels of 8-iso-PGF2α and Gpx were significantly lower in ICP patients than in controls (p = 0.006 and 0.002, respectively), while no significant difference was observed in SOD levels between the two groups. Levels of 8-iso-PGF2α and TBA were negatively correlated (r = -0.277, p = 0.01, Spearman's correlation coefficient).

CONCLUSIONS

The clinical severity of ICP is closely related to the degree of lipid peroxidation, and the natural antioxidant system might fail to work effectively in the presence of lipid peroxidation damage in ICP.

Elevated copper impairs hepatic nuclear receptor function in Wilson's disease

Wilson's disease (WD) is an autosomal recessive disorder that results in accumulation of copper in the liver as a consequence of mutations in the gene encoding the copper-transporting P-type ATPase (ATP7B). WD is a chronic liver disorder, and individuals with the disease present with a variety of complications, including steatosis, cholestasis, cirrhosis, and liver failure. Similar to patients with WD, Atp7b⁻/⁻ mice have markedly elevated levels of hepatic copper and liver pathology. Previous studies have demonstrated that replacement of zinc in the DNA-binding domain of the estrogen receptor (ER) with copper disrupts specific binding to DNA response elements. Here, we found decreased binding of the nuclear receptors FXR, RXR, HNF4α, and LRH-1 to promoter response elements and decreased mRNA expression of nuclear receptor target genes in Atp7b⁻/⁻ mice, as well as in adult and pediatric WD patients. Excessive hepatic copper has been described in progressive familial cholestasis (PFIC), and we found that similar to individuals with WD, patients with PFIC2 or PFIC3 who have clinically elevated hepatic copper levels exhibit impaired nuclear receptor activity. Together, these data demonstrate that copper-mediated nuclear receptor dysfunction disrupts liver function in WD and potentially in other disorders associated with increased hepatic copper levels.

The mechanism of increased biliary lipid secretion in mice with genetic inactivation of bile salt export pump

Human bile salt export pump (BSEP) mutations underlie progressive familial intrahepatic cholestasis type 2 (PFIC2). In the PFIC2 animal model, Bsep(-/-) mice, biliary secretion of bile salts (BS) is decreased, but that of phospholipids (PL) and cholesterol (CH) is increased. Under physiological conditions, the biliary secretion of PL and CH is positively related ("coupled") to that of BS. We aimed to elucidate the mechanism of increased biliary lipid secretion in Bsep(-/-) mice. The secretion of the BS tauro-β-muricholic acid (TβMCA) is relatively preserved in Bsep(-/-) mice. We infused Bsep(-/-) and Bsep(+/+) (control) mice with TβMCA in stepwise increasing dosages (150-600 nmol/min) and determined biliary bile flow, BS, PL, and CH secretion. mRNA and protein expression of relevant canalicular transporters was analyzed in livers from noninfused Bsep(-/-) and control mice. TβMCA infusion increased BS secretion in both Bsep(-/-) and control mice. The secreted PL or CH amount per BS, i.e., the "coupling," was continuously two- to threefold higher in Bsep(-/-) mice (P < 0.05). Hepatic mRNA expression of canalicular lipid transporters Mdr2, Abcg5, and Abcg8 was 45-55% higher in Bsep(-/-) mice (Abcg5; P < 0.05), as was canalicular Mdr2 and Abcg5 protein expression. Potential other explanations for the increased coupling of the biliary secretion of PL and CH to that of BS in Bsep(-/-) mice could be excluded. We conclude that the mechanism of increased biliary lipid secretion in Bsep(-/-) mice is based on increased expression of the responsible canalicular transporter proteins.

Improvement of hepatocyte transplantation efficiency in the mdr2-/- mouse model by glyceryl trinitrate

INTRODUCTION

Hepatocyte transplantation could be an alternative to liver transplantation for the treatment of metabolic diseases. However, rodent models have shown that engraftment of transplanted cells in the liver is low and requires deposition of cells in hepatic sinusoids. Splanchnic vasodilatators improved hepatocyte engraftment in a rat model. Therefore, we investigated the effect of glyceryl trinitrate (GTN) on the efficacy of cell engraftment and on liver repopulation in the mdr2-knockout mouse, a model for progressive familial intrahepatic cholestasis type 3.

METHODS

Congenic normal mdr2 (+/+) hepatocytes were isolated by two-step collagenase perfusion and transplanted into mdr2(-/-) mice livers through the portal vein in the presence or absence of GTN. Liver repopulation was assessed by immunohistochemistry, and transplanted hepatocyte function was assessed at different times after transplantation by measurement of biliary lipid secretion and quantification of fibrosis.

RESULTS

The number of engrafted cells in GTN-treated mice was significantly higher than that in control mice, and transplanted hepatocytes were found in a greater number of distal sinusoids. Levels of phospholipid secretion were significantly higher than those in the control group 3 months after hepatocyte transplantation (18.3 ± 2.3 vs. 5.2 ± 3.9 nmol/min/100 g, P < 0.0001), and the ratio of phospholipids to bile salt was greater (6.8 ± 1.3 vs. 3.2 ± 1.6, P = 0.03). The percentage area of liver fibrosis was also significantly reduced in GTN-treated mice (5.7% ± 2.3% vs. 12.4% ± 2.9%, P = 0.016).

CONCLUSION

The use of GTN improves hepatocyte engraftment and correction of metabolic disease in mdr2 (-/-) mice. This approach might be beneficial in hepatocyte transplantation for the treatment of patients with liver diseases.

[CORRECTION OF BILE FLOW CHARACTERISTICS IN PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE IN COMBINATION WITH HYPERURICEMIA]

Basis on study through integrated comparative assessment of clinical, biochemical survey data revealed that in patients with impaired metabolism of uric acid in a greater percentage of common biliary sludge, a violation of the rheological properties of bile, a violation of cholate-cholesterol ratio index, which indicates an increased risk of bile stones. The study found that despite the high levels of uric acid there is a violation of the spectrum of bile acids, cholic and deoxycholic growth acid reduction taurocholic acid. Thus, application of ursodeoxycholic acid, rosuvastatin and allopurinol in these study patients with NAFLD dosages in combination with hyperuricemia improves the clinical symptoms and normalization of biochemical parameters and normalizes the spectrum of biliary acids.

Liver transcript analysis reveals aberrant splicing due to silent and intronic variations in the ABCB11 gene

BACKGROUND

Progressive familial intrahepatic cholestasis type 2 (PFIC2) is an autosomal recessive disease due to mutations in ABCB11. ABCB11 encodes the bile salt export pump (BSEP), the major transporter responsible for biliary bile acid secretion, which expression is restricted to hepatocytes. In some patients, molecular analysis of ABCB11 revealed either exonic or intronic variations - including common polymorphisms - predicted to affect splicing according to in silico analysis or in vitro minigene studies. Transcript analysis in liver tissue is the best way to determine whether the variations predicted to affect splicing are deleterious or not.

METHODS AND RESULTS

We performed ABCB11 transcript analysis in liver tissue from five PFIC2 patients who had variations which were predicted to either affect splicing or not. Among eleven variants tested, only the silent c.3003A>G variant and the intronic c.3213+4A>G variant led to abnormal splicing as suggested by in silico analysis.

CONCLUSION

ABCB11 liver transcript analysis is a useful tool to confirm or invalidate the predicted splicing effect of a silent or intronic ABCB11 variation.

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

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.

Corticotropin-releasing hormone expression in patients with intrahepatic cholestasis of pregnancy after ursodeoxycholic acid treatment: an initial experience

OBJECTIVE

Corticotropin-releasing hormone (CRH) is one of the most potent vasodilatory factors in the human feto-placental circulation. The expression of CRH was significantly down-regulated in patients with intrahepatic cholestasis of pregnancy (ICP).

METHODS

One hundred pregnant women diagnosed with ICP at 34-34(+6) weeks of gestation agreed to participate in this prospective nested case-control study. Thirty ICP patients were finally recruited in this study, with 16 cases in the ursodeoxycholic acid (UDCA) group (UDCA 750 mg/d) and 14 cases in the control group (Transmetil 1000 mg/d or Essentiale 1368 mg/d). Maternal serum samples were obtained in diagnosis and at 37-37(+6) weeks of gestation. Placental tissues were obtained from participants after delivery. ELISA, enzymatic colorimetric and Western blotting were used to evaluate the concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bile acid (TBA) and CRH in maternal serum and expression of CRH in placenta tissues.

RESULTS

The UDCA group had greater reduction in maternal serum ALT, AST and TBA levels in ICP patients (all p < 0.01). Maternal serum CRH concentrations in the UDCA group after treatment (122.10 ± 44.20) pg/ml was significantly higher than pretreatment (95.45 ± 26.47) pg/ml (p < 0.01). After treatment, maternal serum CRH concentrations of the UDCA group (122.10 ± 44.20) pg/ml was significantly higher than in the control group (80.71 ± 41.10) pg/ml (p < 0.01). Placental CRH expression in the UDCA group (2.79 ± 1.72) was significantly higher than in the control group (0.69 ± 0.36) (p < 0.01).

CONCLUSIONS

Maternal serum and placental CRH expression in ICP patients were up-regulated after treatment of UDCA. The up-regulation of CRH expression after UDCA treatment may play an important role in the therapeutic mechanism of ICP. All patients recruited in this study had severe cholestasis (TBA ≥ 40 µmol/L). Further studies are warranted in different gestational weeks and TBA levels to provide more evidence for the correlation between UDCA treatment and CRH expression in ICP patients.

Altered expression and function of canalicular transporters during early development of cholestatic liver injury in Abcb4-deficient mice

Deficiency of ABCB4 is associated with several forms of cholestasis in humans. Abcb4(-/-) mice also develop cholestasis, but it remains uncertain what role other canalicular transporters play in the development of this disease. We examined the expression of these transporters in Abcb4(-/-) mice compared with their wild-type littermate controls at ages of 10 days and 3, 6, and 12 wk. Elevated plasma bile acid levels were already detected at 10 days and at all ages thereafter in Abcb4(-/-) mice. The expression of Bsep, Mrp2, Atp8b1, Abcg5, and Abcg8 liver proteins did not change at 10 days, but Bsep, Mrp2, and Atp8b1 were reduced, whereas Abcg5 and Abcg8 expression were increased in Abcb4(-/-) mice at all later ages. Lower bile acid concentrations were also detected in the bile of 6-wk-old Abcb4(-/-) mice. Immunofluorescence labeling revealed distorted canalicular architecture in the liver tissue by 12 wk in Abcb4(-/-) mice. Whereas Bsep and Mrp2 remained associated with the apical membrane, Atp8b1 was now localized in discrete punctuate structures adjacent to the canalicular membrane in these mice. Expression of Bsep mRNA was increased in the livers of 10-day-old Abcb4(-/-) mice, whereas Ost-α was decreased. By 12 wk, Bsep, Mrp2, and Abcg5 mRNA were all increased, whereas Ost-α and Ntcp were reduced. These findings indicate that canalicular transporters that determine the formation of bile are altered early in the development of cholestasis in Abcb4(-/-) mice and may contribute to the pathogenesis of cholestasis in this disorder.

[Effect of emodin on expression of farnesoid X receptor in rats with acute cholestatic hepatitis]

OBJECTIVE

To investigate the expression of farnesoid X receptor (FXR) and the effect of emodin on FXR expression in a rat model of acute cholestatic hepatitis.

METHODS

Ninety adult Sprague-Dawley rats were randomly divided into normal control, model, and emodin groups (n=30 each). The model and emodin groups were given alpha-naphthylisothiocyanate (ANIT) 50 mg/kg by gavage to establish an animal model of cholestatic hepatitis, while the normal control group was given an equal volume of sesame oil. The emodin group was given emodin by gavage every day from 4 days before the model was prepared until the time of sacrifice, while the model and normal control groups were given an equal volume of sodium carboxymethyl cellulose solution. At 24, 48 and 72 hours after the model was prepared, serum level of total bilirubin (TB), direct bilirubin (DB), alanine aminotransferase (ALT), and total bile acids (TBA) were measured by Aeroset automatic biochemical analyzer, and the mRNA expression of FXR in the liver tissue was measured by real-time PCR.

RESULTS

At all time points FXR mRNA expression in the model group decreased, but serum levels of TB, DB, ALT and TBA increased significantly compared with the normal control group (P<0.05). The emodin group had significantly higher mRNA expression of FXR and significantly lower serum levels of TB, DB, ALT, and TBA compared with the model group (P<0.05).

CONCLUSIONS

Emodin can significantly reduce serum levels of TB, DB, ALT, and TBA in rats with ANIT-induced cholestatic hepatitis, probably by promoting FXR expression.

Metformin interferes with bile acid homeostasis through AMPK-FXR crosstalk

The nuclear bile acid receptor farnesoid X receptor (FXR) is an important transcriptional regulator of bile acid, lipid, and glucose metabolism. FXR is highly expressed in the liver and intestine and controls the synthesis and enterohepatic circulation of bile acids. However, little is known about FXR-associated proteins that contribute to metabolic regulation. Here, we performed a mass spectrometry-based search for FXR-interacting proteins in human hepatoma cells and identified AMPK as a coregulator of FXR. FXR interacted with the nutrient-sensitive kinase AMPK in the cytoplasm of target cells and was phosphorylated in its hinge domain. In cultured human and murine hepatocytes and enterocytes, pharmacological activation of AMPK inhibited FXR transcriptional activity and prevented FXR coactivator recruitment to promoters of FXR-regulated genes. Furthermore, treatment with AMPK activators, including the antidiabetic biguanide metformin, inhibited FXR agonist induction of FXR target genes in mouse liver and intestine. In a mouse model of intrahepatic cholestasis, metformin treatment induced FXR phosphorylation, perturbed bile acid homeostasis, and worsened liver injury. Together, our data indicate that AMPK directly phosphorylates and regulates FXR transcriptional activity to precipitate liver injury under conditions favoring cholestasis.

Promoter DNA methylation of farnesoid X receptor and pregnane X receptor modulates the intrahepatic cholestasis of pregnancy phenotype

The intrahepatic cholestasis of pregnancy (ICP) is a multifactorial liver disorder which pathogenesis involves the interplay among abnormal bile acid (BA) levels, sex hormones, environmental factors, and genetic susceptibility. The dynamic nature of ICP that usually resolves soon after delivery suggests the possibility that its pathobiology is under epigenetic modulation. We explored the status of white blood peripheral cells-DNA methylation of CpG-enriched sites at the promoter of targeted genes (FXR/NR1H4, PXR/NR1I2, NR1I3, ESR1, and ABCC2) in a sample of 88 ICP patients and 173 healthy pregnant women in the third trimester of their pregnancies. CpG dinucleotides at the gene promoter of nuclear receptors subfamily 1 members and ABCC2 transporter were highly methylated during healthy pregnancy. We observed significant differences at the distal (−1890) and proximal promoter (−358) CpG sites of the FXR/NR1H4 and at the distal PXR/NR1I2 (−1224) promoter, which were consistently less methylated in ICP cases when compared with controls. In addition, we observed that methylation at FXR/NR1H4-1890 and PXR/NR1I2-1224 promoter sites was highly and positively correlated with BA profiling, particularly, conjugated BAs. Conversely, methylation level at the proximal FXR/NR1H4-358 CpG site was significantly and negatively correlated with the primary cholic and secondary deoxycholic acid. In vitro exploration showed that epiallopregnanolone sulfate, a reported FXR inhibitor, regulates the transcriptional activity of FXR/NR1H4 but seems to be not involved in the methylation changes. In conclusion, the identification of epigenetic marks in target genes provides a basis for the understanding of adverse liver-related pregnancy outcomes, including ICP.

Roles of PPARγ/NF-κB signaling pathway in the pathogenesis of intrahepatic cholestasis of pregnancy

Background

Intrahepatic cholestasis of pregnancy (ICP) is the most prevalent pregnancy specific liver disease. However, the pathogenesis and etiology of ICP is poorly understood.

Aim

To assess the expression of peroxisome proliferator-activated receptorγ (PPARγ) and nuclear factor kappa B (NF-κB) in placenta and HTR-8/SVneo cell, and evaluate the serum levels of cytokines, bile acids, hepatic function and lipids in control and ICP patients and the fetal outcome, in order to explore the role of PPARγ/NF-κB signaling pathway in the possible mechanism of ICP.

Methods

Clinical data of the pregnant women were collected and serum levels of cytokines, bile acids, hepatic function and lipids were measured. Expressions of PPARγ and NF-κB in placenta and HTR-8/SVneo cell were determined. The new-born information was collected to demonstrate the relationship between PPARγ/NF-κB signaling pathway and ICP.

Results

The serum levels of bile acids, hepatic function, triglycerides (TG), total cholesterol (TC), IL-6, IL-12 and TNF-α in ICP group were significantly increased (P<0.01), and serum level of IL-4 was significantly decreased (P<0.01). PPARγ and NF-κB staining were found in the membrane and cytoplasm of placental trophoblast cell. The expression of PPARγ and NF-κB were significantly higher in ICP group and taurocholate acid (TCA) treated HTR-8/SVneo cell (P<0.01). The new-born information in severe ICP group were significantly different as compared to that in control group (P<0.05), and part of information in mild ICP group were also difference to that in control group (P<0.05).

Conclusions

The higher expressions of PPARγ and NF-κB in ICP placenta and TCA treated HTR-8/SVneo cell, together with the abnormal serum levels of cytokines, might induced by the imbalance of inflammatory and immune reaction, and then disturb placental bile acid and serum lipids transportation, finally result in fatal cholestasis which probably be one of the mechanism of ICP.

Comparative proteomics analysis of placenta from pregnant women with intrahepatic cholestasis of pregnancy

Introduction

Intrahepatic cholestasis of pregnancy (ICP) usually occurs in the third trimester and associated with increased risks in fetal complications. Currently, the exact cause of this disease is unknown. In this study we aim to investigate the potential proteins in placenta, which may participate in the molecular mechanisms of ICP-related fetal complications using iTRAQ-based proteomics approach.

Methods

The iTRAQ analysis combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to separate differentially expressed placental proteins from 4 pregnant women with ICP and 4 healthy pregnant women. Bioinformatics analysis was used to find the relative processes that these differentially expressed proteins were involved in. Three apoptosis related proteins ERp29, PRDX6 and MPO that resulted from iTRAQ-based proteomics were further verified in placenta by Western blotting and immunohistochemistry. Placental apoptosis was also detected by TUNEL assay.

Results

Proteomics results showed there were 38 differentially expressed proteins from pregnant women with ICP and healthy pregnant women, 29 were upregulated and 9 were downregulated in placenta from pregnant women with ICP. Bioinformatics analysis showed most of the identified proteins was functionally related to specific cell processes, including apoptosis, oxidative stress, lipid metabolism. The expression levels of ERp29, PRDX6 and MPO were consistent with the proteomics data. The apoptosis index in placenta from ICP patients was significantly increased.

Conclusion

This preliminary work provides a better understanding of the proteomic alterations of placenta from pregnant women with ICP and may provide us some new insights into the pathophysiology and potential novel treatment targets for ICP.