Effect of ursodeoxycholic acid treatment on the altered progesterone and bile acid homeostasis in the mother-placenta-foetus trio during cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy and its association with preeclampsia and gestational diabetes: a retrospective analysis

PURPOSE

To evaluate maternal and neonatal outcomes in patients with intrahepatic cholestasis of pregnancy (ICP).

METHODS

Patients who gave birth in our hospital between January 2018 and March 2022 were retrospectively reviewed from the hospital database and patient file records. The study comprised 1686 patients, 54 in the ICP group and 1632 controls. Patients who had ICP after 20 weeks of gestation and were monitored and delivered at our facility were enrolled. Maternal demographic and obstetric characteristics data were examined. Perinatal outcomes were also assessed. Logistic regression analysis was used to determine adverse maternal outcomes.

RESULTS

The mean age was 29 years. ART, GDM, and preeclampsia were significantly higher in the ICP group. The mean serum bile acid level was 19.3 ± 3 μmol/L in the ICP group. There was a higher risk of GDM and pre-eclampsia in women with ICP compared with those without and a significant association between ICP and adverse perinatal outcomes. There was a statistically significant relation between the presence of ICP and spontaneous preterm delivery, iatrogenic preterm delivery, 5th-minute Apgar scores < 7, and NICU requirement. No significant relationship was found between the presence of ICP and SGA and meconium. There was a significant relationship between the presence of ICP, mode of delivery, and PPH (p < 0.05). Those with ICP had a lower gestational week and birth weight, and higher rates of cesarean delivery and PPH.

CONCLUSION

ICP should prompt close monitoring and management to mitigate the potential exacerbation of adverse outcomes, including preeclampsia, GDM, and preterm birth.

Association of cord plasma metabolites with birth weight: results from metabolomic and lipidomic studies of discovery and validation cohorts

OBJECTIVE

Birth weight is a good predictor of fetal intrauterine growth and long-term health, and several studies have evaluated the relationship between metabolites and birth weight. The aim of this study was to investigate the association of cord blood metabolomics and lipidomics with birth weight, using a two-stage discovery and validation approach.

METHODS

Firstly, a pseudotargeted metabolomics approach was applied to detect metabolites in 504 cord blood samples in the discovery set enrolled from the Wuhan Healthy Baby Cohort, China. Metabolome-wide association scan analysis and pathway enrichment were applied to identify metabolites and metabolic pathways that were significantly associated with birth weight adjusted for gestational age Z-score (BW Z-score). Logistic regression models were used to analyze the association of metabolites in the most significantly associated pathways with small-for-gestational age (SGA) at delivery and low birth weight (LBW). Subsequently, 350 cord blood samples in a validation cohort were subjected to targeted analysis to validate the metabolites identified by screening in the discovery cohort.

RESULTS

In the discovery set, of 2566 metabolites detected, 2418 metabolites were retained for subsequent analysis after data preprocessing. Of these, 513 metabolites were significantly associated with BW Z-score (P-value adjusted for false discovery rate (PFDR) < 0.05), of which 298 Kyoto Encyclopedia of Genes and Genomes (KEGG)-annotated metabolites were included in the pathway analysis. The primary bile acid biosynthesis pathway was the most relevant metabolic pathway associated with BW Z-score. Elevated cord plasma primary bile acids were associated with lower BW Z-score and higher risk of SGA or LBW in the discovery and validation cohorts. In the validation set, a 2-fold increase in taurochenodeoxycholic acid (TCDCA) and in taurocholic acid (TCA) was associated with a decrease in BW Z-score (estimated β coefficient, -0.10 (95% CI, -0.20 to 0.00) and -0.18 (95% CI, -0.31 to -0.04), respectively), after adjusting for covariates. In addition, a 2-fold increase in cord plasma TCDCA and of cord plasma TCA was associated with an increased risk of SGA (adjusted odds ratio (OR), 1.52 (95% CI, 1.00-2.30) and 1.77 (95% CI, 1.05-2.98), respectively). The adjusted OR for LBW, for a 2-fold increase in TCDCA and TCA concentration, were 2.39 (95% CI, 1.00-5.71) and 3.21 (95% CI, 0.96-10.74), respectively.

CONCLUSIONS

These results indicate a significant association of elevated primary bile acids, particularly TCDCA and TCA, in cord blood with lower BW Z-score, as well as increased risk of SGA and LBW. Abnormalities of primary bile acid metabolism may play an important role in restricted fetal development. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Gradual dosing of ursodeoxycholic acid in mothers with intrahepatic cholestasis of pregnancy may improve composite neonatal outcome

INTRODUCTION AND OBJECTIVES

Intrahepatic cholestasis of pregnancy (ICP) is often accompanied by fetal and maternal complications.

MATERIALS AND METHODS

Retrospective review of the clinical course of women with ICP and their neonates treated at our medical center over a 10-year period. Special attention was paid to the maternal and neonatal response to 2 different modes of ursodeoxycholic acid (UDCA) administration.

RESULTS

Neonates of mothers with high total bile acid levels had a poorer composite neonatal outcome. Twenty-seven women who presented at an advanced stage of their pregnancies did not receive UDCA. UDCA was administered in 2 modes: either a full dose at admission (76 women) or a gradually increasing dose until the desired dosage was reached (25 women). The mean gestational age at delivery for the 94 neonates that were exposed to full UDCA dose was the lowest (36±2.3 weeks for the full dose, 37±1.4 weeks for the 30 neonates from the gradually increasing dose, 38±1.6 weeks for the 29 neonates from the no treatment group, p<0.001). The group of neonates that were exposed to full UDCA dose had the highest rate of unfavorable composite neonatal outcome (53% for full dose, 30% for gradually increasing dose, 24% for the no treatment group, p=0.006).

CONCLUSIONS

Compared to the administration of a full UDCA dose, the administration of a gradually increasing dose of UDCA may be associated with a greater gestational age at delivery and fewer events of unfavorable composite neonatal outcomes. These novel findings should be retested prospectively in a large cohort of patients.

Relationship between cholestasis and altered progesterone metabolism in the placenta-maternal liver tandem

BACKGROUND

In intrahepatic cholestasis of pregnancy (ICP), there are elevated maternal serum levels of total bile acids, progesterone, and some sulfated metabolites, such as allopregnanolone sulfate, which inhibits canalicular function.

AIM

To investigate the relationship between cholestasis and the expression of crucial enzymes involved in progesterone metabolism in the liver and placenta.

METHODS

Obstructive cholestasis was induced by bile duct ligation (BDL). RT-qPCR (mRNA) and western blot (protein) were used to determine expression levels. Srd5a1 and Akr1c2 enzymatic activities were assayed by substrate disappearance (progesterone and 5α-dihydroprogesterone, respectively), measured by HPLC-MS/MS.

RESULTS

BDL induced decreased Srd5a1 and Akr1c2 expression and activity in rat liver, whereas both enzymes were up-regulated in rat placenta. Regarding sulfotransferases, Sult2b1 was also moderately up-regulated in the liver. In placenta from ICP patients, SRD5A1 and AKR1C2 expression was elevated, whereas both genes were down-regulated in liver biopsies collected from patients with several liver diseases accompanied by cholestasis. SRD5A1 and AKR1C2 expression was not affected by incubating human hepatoma HepG2 cells with FXR agonists (chenodeoxycholic acid and GW4064). Knocking-out Fxr in mice did not reduce Srd5a1 and Akr1c14 expression, which was similarly down-regulated by BDL.

CONCLUSION

SRD5A1 and AKR1C2 expression was markedly altered by cholestasis. This was enhanced in the placenta but decreased in the liver, which is not mediated by FXR. These results suggest that the excess of progesterone metabolites in the serum of ICP patients can involve both enhanced placental production and decreased hepatic clearance. The latter may also occur in other cholestatic conditions.

Maternal and Neonatal Outcomes in Intrahepatic Cholestasis of Pregnancy

The aims of our study were to evaluate the maternal and fetal outcomes of intrahepatic cholestasis of pregnancy (ICP). In this observational, retrospective case-control study, we included all pregnant women who gave birth with a diagnosis of ICP between January 2010 and December 2020 at the Unit of Obstetrics and Gynecology, University Hospital of Messina. The data were compared with those from a control group of pregnant women who did not have ICP. One hundred twenty-nine and eighty-five patients were included, respectively, in the study and in the control group. There was a significant difference between the two groups in the incidence of hypothyroidism, thrombophilia, gestational diabetes, gestational hypertension, postpartum hemorrhage, and preterm delivery, which were more frequent in the ICP patients. No neonatal adverse events were recorded, although a significant difference in the meconium-stained amniotic fluid condition was noted. After a 24-month follow-up, 48/129 patients with ICP accepted to be reassessed by liver ultrasound, elastographic examination, and liver function blood tests. No patient showed signs of chronic liver disease. This study confirmed a higher probability of adverse short-term maternal outcomes in ICP pregnant patients, but a lower probability of adverse short-term fetal outcomes and the absence of a long-term maternal risk of chronic liver disease.

Gut microbiota involved in desulfation of sulfated progesterone metabolites: A potential regulation pathway of maternal bile acid homeostasis during pregnancy

Abnormally raised circulating bile acids (BA) during pregnancy threat fetal and offspring health. Our previous study has identified sulfated progesterone metabolites (PMSs) in part account for dysregulation of maternal BA homeostasis during pregnancy, however, limited intervention strategies to remedy increased serum BA through PMSs during pregnancy are available. The purpose of this study is to test the feasibility of manipulating BA homeostasis and progesterone metabolism through steering gut microbiota. A total of 19 pregnant sows were randomly treated with standard diet or vancomycin-supplemented diet, to investigate the intercorrelation of PMSs, intestinal microbiota, and maternal BA metabolism from day 60 of gestation (G60) until farrowing (L0). Pregnant mice orally gavaged with epiallopregnanolone sulfate (PM5S) or vehicle and nonpregnant mice were sampled and further analyzed to verify the effect of PM5S on maternal BA metabolism. The present study revealed that oral vancomycin reduced maternal fasting serum total BA (TBA) levels and postprandial serum TBA levels at day 90 of gestation (G90). BA profile analysis showed the decreased TBA after vancomycin treatment was attributed to the decrease of primary BA and secondary BA, especially hyodeoxycholic acid (HDCA). By using newly developed UPLC-MS/MS methods, we found vancomycin increased fecal excretion of allopregnanolone sulfate (PM4S) and PM5S during late gestation and thus maintaining the relative stability of serum PM4S and PM5S, which play an important role in BA metabolism. Further study in mice showed that pregnant mice have higher serum and liver TBA levels compared with nonpregnant mice, and PM5S administration induced higher gallbladder TBA levels and TBA pool in pregnant mice. In addition, after oral vancomycin, the continuously decreased Parabacteroides genus, potentially enriched with genes encoding steroids sulfatase, may explain the increased fecal PMSs excretion in pregnant sows. Taken together, our study provides the evidence that pregnancy-induced elevation of BA levels in sow is likely regulated by manipulation of gut microbiota, which offer new insights into the prevention and treatment of disrupted BA homeostasis during pregnancy by targeting specific microbiota.

Maternal and Fetal Bile Acid Homeostasis Regulated by Sulfated Progesterone Metabolites through FXR Signaling Pathway in a Pregnant Sow Model

Abnormally elevated circulating bile acids (BA) during pregnancy endanger fetal survival and offspring health; however, the pathology and underlying mechanisms are poorly understood. A total of nineteen pregnant sows were randomly assigned to day 60 of gestation, day 90 of gestation (G60, G90), and the farrowing day (L0), to investigate the intercorrelation of reproductive hormone, including estradiol, progesterone and sulfated progesterone metabolites (PMSs), and BA in the peripheral blood of mother and fetuses during pregnancy. All data were analyzed by Student's t-test or one-way ANOVA of GraphPad Prism and further compared by using the Student-Newman-Keuls test. Correlation analysis was also carried out using the CORR procedure of SAS to study the relationship between PMSs and BA levels in both maternal and fetal serum at G60, G90, and L0. Allopregnanolone sulphate (PM4S) and epiallopregnanolone sulphate (PM5S) were firstly identified in the maternal and fetal peripheral blood of pregnant sows by using newly developed ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) methods. Correlation analysis showed that pregnancy-associated maternal BA homeostasis was correlated with maternal serum PM4S levels, whereas fetal BA homeostasis was correlated with fetal serum PM5S levels. The antagonist activity role of PM5S on farnesoid X receptor (FXR)-mediated BA homeostasis and fibroblast growth factor 19 (FGF19) were confirmed in the PM5S and FXR activator co-treated pig primary hepatocytes model, and the antagonist role of PM4S on FXR-mediated BA homeostasis and FGF19 were also identified in the PM4S-treated pig primary hepatocytes model. Together with the high relative expression of FGF19 in pig hepatocytes, the pregnant sow is a promising animal model to investigate the pathogenesis of cholestasis during pregnancy.

Inclusion of Soluble Fiber During Gestation Regulates Gut Microbiota, Improves Bile Acid Homeostasis, and Enhances the Reproductive Performance of Sows

Interaction between the dietary fiber and the gut microbes can regulate host bile acid metabolism. This study sought to explore the effects of guar gum combined with pregelatinized waxy maize starch (GCW) in a gestation diet on reproductive performance, gut microbiota composition, and bile acid homeostasis of sows. A total of 61 large white sows were randomly grouped into the control (n = 33) and 2% GCW (n = 28) groups during gestation. GCW diet increased birth-weight of piglets, and decreased the percentage of intrauterine growth restriction (IUGR) piglets. In addition, dietary GCW reduced gut microbial diversity and modulated gut microbial composition in sows on day 109 of gestation. The relative abundance of bile salt hydrolase (BSH) gene-encoding bacteria, Lactobacillus and Bacteroides decreased after GCW administration, whereas no significant difference was observed in the fecal level of total glycine-conjugated and taurine-conjugated bile acids between the two groups. Dietary GCW increased the relative abundance of Ruminococcaceae (one of few taxa comprising 7α-dehydroxylating bacteria), which was associated with elevated fecal deoxycholic acid (DCA) in the GCW group. GCW administration lowered the concentrations of plasma total bile acid (TBA) and 7α-hydroxy-4-cholesten-3-one (C4) (reflecting lower hepatic bile acid synthesis) at day 90 and day 109 of gestation compared with the control diet. Furthermore, the levels of plasma glycoursodeoxycholic acid (GUDCA), tauroursodeoxycholic acid (TUDCA) and glycohyocholic acid (GHCA) were lower in the GCW group compared with the control group. Spearman correlation analysis showed alterations in the composition of the gut microbiota by GCW treatment was associated with improved bile acid homeostasis and reproductive performance of sows. In conclusion, GCW-induced improves bile acid homeostasis during gestation which may enhance reproductive performance of sows.

Ursodeoxycholic acid in intrahepatic cholestasis of pregnancy: a systematic review and individual participant data meta-analysis

BACKGROUND

Ursodeoxycholic acid is commonly used to treat intrahepatic cholestasis of pregnancy, yet its largest trial detected minimal benefit for a composite outcome (stillbirth, preterm birth, and neonatal unit admission). We aimed to examine whether ursodeoxycholic acid affects specific adverse perinatal outcomes.

METHODS

In this systematic review and individual participant data meta-analysis, we searched PubMed, Web of Science, Embase, MEDLINE, CINAHL, Global Health, MIDIRS, and Cochrane without language restrictions for relevant articles published between database inception, and Jan 1, 2020, using search terms referencing intrahepatic cholestasis of pregnancy, ursodeoxycholic acid, and perinatal outcomes. Eligible studies had 30 or more study participants and reported on at least one individual with intrahepatic cholestasis of pregnancy and bile acid concentrations of 40 μmol/L or more. We also included two unpublished cohort studies. Individual participant data were collected from the authors of selected studies. The primary outcome was the prevalence of stillbirth, for which we anticipated there would be insufficient data to achieve statistical power. Therefore, we included a composite of stillbirth and preterm birth as a main secondary outcome. A mixed-effects meta-analysis was done using multi-level modelling and adjusting for bile acid concentration, parity, and multifetal pregnancy. Individual participant data analyses were done for all studies and in different subgroups, which were produced by limiting analyses to randomised controlled trials only, singleton pregnancies only, or two-arm studies only. This study is registered with PROSPERO, CRD42019131495.

FINDINGS

The authors of the 85 studies fulfilling our inclusion criteria were contacted. Individual participant data from 6974 women in 34 studies were included in the meta-analysis, of whom 4726 (67·8%) took ursodeoxycholic acid. Stillbirth occurred in 35 (0·7%) of 5097 fetuses among women with intrahepatic cholestasis of pregnancy treated with ursodeoxycholic acid and in 12 (0·6%) of 2038 fetuses among women with intrahepatic cholestasis of pregnancy not treated with ursodeoxycholic acid (adjusted odds ratio [aOR] 1·04, 95% CI 0·35-3·07; p=0·95). Ursodeoxycholic acid treatment also had no effect on the prevalence of stillbirth when considering only randomised controlled trials (aOR 0·29, 95% CI 0·04-2·42; p=0·25). Ursodeoxycholic acid treatment had no effect on the prevalence of the composite outcome in all studies (aOR 1·28, 95% CI 0·86-1·91; p=0·22), but was associated with a reduced composite outcome when considering only randomised controlled trials (0·60, 0·39-0·91; p=0·016).

INTERPRETATION

Ursodeoxycholic acid treatment had no significant effect on the prevalence of stillbirth in women with intrahepatic cholestasis of pregnancy, but our analysis was probably limited by the low overall event rate. However, when considering only randomised controlled trials, ursodeoxycholic acid was associated with a reduction in stillbirth in combination with preterm birth, providing evidence for the clinical benefit of antenatal ursodeoxycholic acid treatment.

FUNDING

Tommy's, the Wellcome Trust, ICP Support, and the National Institute for Health Research.

The role of genetic mutations in intrahepatic cholestasis of pregnancy

OBJECTIVE

Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder of pregnancy characterized by pruritus, elevated liver enzymes and fasting serum bile acids. Genetic predisposition has been suggested to play a role in its etiology and mutations in the ATP8B1(OMIM ∗602397) (FIC1), ABCB11(OMIM ∗603201) (BSEP), and ABCB4(OMIM ∗171060) (MDR3) genes have been implicated. In the present study, we aimed to investigate the possible role of ATP8B1, ABCB11, and ABCB4 gene mutations in the patients with ICP.

MATERIALS AND METHODS

A total of 25 patients who were diagnosed with ICP were included in the study. Genetic test results and mutation status of the patients as assessed by the next-generation sequencing technology were retrospectively retrieved from the hospital database.

RESULTS

Of all patients, significant alterations in the ATP8B1 (n = 2), ABCB11 (n = 1), and ABCB4 (n = 7) genes were observed in 10 patients using the molecular analysis testing. All these alterations were heterozygous. Of these alterations, four were reported in the literature previously, while six were not. Using the in-silico parameters, there was a pathogenic alteration in the ABCB4 gene in one patient, while there was no clinically relevant alteration in the other gene mutations in the remaining nine patients.

CONCLUSION

Considering the fact that the alterations were compatible with clinical presentations of the ICP patients and the incidence of these mutations is low in the general population, we believe that our study results are clinically relevant. Further molecular genetic tests in ICP patients and functional studies supporting the results would shed light into the clinical importance of these alterations.

Predictive factors associated with disease recurrence in patients with severe intrahepatic cholestasis of pregnancy: a retrospective study of 118 cases

PURPOSE

To compare the clinical characteristics of pregnant women and perinatal outcomes with or without recurrent severe intrahepatic cholestasis of pregnancy (sICP), and identify possible factors associated with disease recurrence.

METHODS

A retrospective study of 164,603 deliveries was performed to identify pregnant women diagnosed with sICP in the previous pregnancy from January 2012 to December 2020. Eligible patients were divided into two subgroups according to the status of disease recurrence in the second pregnancy: recurrent severe ICP (r-sICP) and non-recurrent severe ICP (nr-sICP). Demographics, clinical characteristics, maternal and perinatal outcomes, and potential factors linked to disease recurrence were analyzed.

RESULTS

Totally 118 patients were enrolled and respectively classified into the r-sICP group (n = 63) and the nr-sICP group (n = 55). The proportion of hepatitis B virus (HBV) infection (HBsAg+, HBeAg+, HBcAb+) and early-onset ICP (<28 weeks) in the r-sICP group in the previous pregnancy were higher than those in the nr-sICP group. In the second delivery, neonatal outcomes in the r-sICP group were worse than those in the nr-sICP group. Logistic regression analysis of predictive factors for disease recurrence in the second delivery revealed that the combination of HBV infection and early-onset ICP in the previous delivery had the steepest receiver-operating characteristic (ROC) curve value 0.720 (95%CI: 0.629-0.812).

CONCLUSION

Patients with sICP displayed a higher recurrence rate in the second pregnancy. Being <28 weeks at the time of ICP diagnosis and having HBV infection in the previous delivery appear to be independent predictive factors for disease recurrence of sICP.

Whole-exome sequencing identifies novel mutations in ABC transporter genes associated with intrahepatic cholestasis of pregnancy disease: a case-control study

Background

Intrahepatic cholestasis of pregnancy (ICP) can cause premature delivery and stillbirth. Previous studies have reported that mutations in ABC transporter genes strongly influence the transport of bile salts. However, to date, their effects are still largely elusive.

Methods

A whole-exome sequencing (WES) approach was used to detect novel variants. Rare novel exonic variants (minor allele frequencies: MAF < 1%) were analyzed. Three web-available tools, namely, SIFT, Mutation Taster and FATHMM, were used to predict protein damage. Protein structure modeling and comparisons between reference and modified protein structures were performed by SWISS-MODEL and Chimera 1.14rc, respectively.

Results

We detected a total of 2953 mutations in 44 ABC family transporter genes. When the MAF of loci was controlled in all databases at less than 0.01, 320 mutations were reserved for further analysis. Among these mutations, 42 were novel. We classified these loci into four groups (the damaging, probably damaging, possibly damaging, and neutral groups) according to the prediction results, of which 7 novel possible pathogenic mutations were identified that were located in known functional genes, including ABCB4 (Trp708Ter, Gly527Glu and Lys386Glu), ABCB11 (Gln1194Ter, Gln605Pro and Leu589Met) and ABCC2 (Ser1342Tyr), in the damaging group. New mutations in the first two genes were reported in our recent article. In addition, compared to the wild-type protein structure, the ABCC2 Ser1342Tyr-modified protein structure showed a slight change in the chemical bond lengths of ATP ligand-binding amino acid side chains. In placental tissue, the expression level of the ABCC2 gene in patients with ICP was significantly higher (P < 0.05) than that in healthy pregnant women. In particular, the patients with two mutations in ABC family genes had higher average values of total bile acids (TBA), aspartate transaminase (AST), direct bilirubin (DBIL), total cholesterol (CHOL), triglycerides (TG) and high-density lipoprotein (HDL) than the patients who had one mutation, no mutation in ABC genes and local controls.

Conclusions

Our present study provide new insight into the genetic architecture of ICP and will benefit the final identification of the underlying mutations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03595-x.

Ursodeoxycholic acid improves pregnancy outcome in patients with intrahepatic cholestasis during pregnancy: A protocol for systematic review and meta-analysis

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is a common complication in the third trimester of pregnancy, which may result in premature delivery, fetal distress, stillbirth, and other adverse pregnancy outcomes. Ursodeoxycholic acid (UDCA) is a first-line treatment for ICP and has been controversial in improving adverse pregnancy outcomes. The purpose of this protocol is to systematically evaluate the effect of UDCA on pregnancy outcomes in patients with intrahepatic cholestasis during pregnancy.

METHODS

To search the databases PubMed, Embase, Web of Science, the Cochrane Library, CNKI, WanFang, VIP, CBMDIsc by computer, then to include randomized controlled clinical studies on UDCA for treatment of intrahepatic cholestasis during pregnancy from the establishment of the database to October 1, 2020. Two researchers independently extract and evaluate the data of the included studies, and meta-analysis is conducted on the included literatures using RevMan5.3 software.

RESULTS

This protocol evaluates the outcome of UDCA in improving ICP by incidence of postpartum hemorrhage in pregnant women preterm birth rates meconium contamination rate in amniotic fluid incidence of fetal distress scale of newborns scoring <7 in 5-min Apgar incidence of neonatal admission to neonatal intensive care unit.

CONCLUSION

This protocol will provide an evidence-based basis for clinical use of UDCA in the treatment of intrahepatic cholestasis during pregnancy.

ETHICS AND DISSEMINATION

Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval was not required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605 / OSF.IO / BE67H.

An insight into the mechanism and molecular basis of dysfunctional immune response involved in cholestasis

Cholestasis is one of the most common clinical symptom of liver diseases. If patients do not receive effective treatment, cholestasis can evolve into liver fibrosis, cirrhosis and ultimately liver failure requiring liver transplantation. Currently, only ursodeoxycholic acid, obeticholic acid and bezafibrate are FDA-approved drugs, thereby requiring a breakthrough in new mechanisms and therapeutic development. Inflammation is one of the common complications of cholestasis. Hepatic accumulation of toxic hydrophobic bile acids is a highly immunogenic process involving both resident and immigrating immune cells. And the resulting inflammation may further aggravate hepatocyte injury. Though, great investigations have been made in the immune responses during cholestasis, the relationship between immune responses and cholestasis remains unclear. Moreover, scarce reviews summarize the immune responses during cholestasis and the efficacy of therapies on immune response. The main purpose of this paper is to review the existing literature on dysfunctional immune response during cholestasis and the effect of treatment on immune response which may provide an insight for researchers and drug development.

Intrahepatic Cholestasis of Pregnancy: Natural History and Current Management

Intrahepatic cholestasis of pregnancy (ICP) is a common disorder in the second half of pregnancy characterized by pruritus and elevated serum bile acids (BAs) with spontaneous resolution after delivery. ICP carries a risk of adverse effects on the fetus which correlates with the degree of BA elevation. ICP occurs in genetically susceptible women as the reproductive hormones increase during pregnancy. Ursodeoxycholic acid is still considered the first-line treatment for ICP though it is of unproven benefit in preventing adverse effects on the fetus. Fetal complications, such as stillbirth, increase with gestational age, so preterm delivery is generally performed in cases of severe ICP, defined as BA levels above 40 μmol/L. ICP may recur in future pregnancies and is associated with an increased risk for future hepatobiliary, immune mediated, and cardiovascular diseases. Children born of mothers with ICP have normal development but may have a risk for subsequent metabolic disease.

Contributions of Drug Transporters to Blood-Placental Barrier

The placenta is the only organ linking two different individuals, mother and fetus, termed as blood-placental barrier. The functions of the blood-placental barrier are to regulate material transfer between the maternal and fetal circulation. The main functional units are the chorionic villi within which fetal blood is separated by only three or four cell layers (placental membrane) from maternal blood in the surrounding intervillous space. A series of drug transporters such as P-glycoprotein (P-GP), breast cancer resistance protein (BCRP), multidrug resistance-associated proteins (MRP1, MRP2, MRP3, MRP4, and MRP5), organic anion-transporting polypeptides (OATP4A1, OATP1A2, OATP1B3, and OATP3A1), organic anion transporter 4 (OAT4), organic cation transporter 3 (OCT3), organic cation/carnitine transporters (OCTN1 and OCTN2), multidrug and toxin extrusion 1 (MATE1), and equilibrative nucleoside transporters (ENT1 and ENT2) have been demonstrated on the apical membrane of syncytiotrophoblast, some of which also expressed on the basolateral membrane of syncytiotrophoblast or fetal capillary endothelium. These transporters are involved in transport of most drugs in the placenta, in turn, affecting drug distribution in fetus. Moreover, expressions of these transporters in the placenta often vary along with the gestational ages and are also affected by pathophysiological factor. This chapter will mainly illustrate function and expression of these transporters in placentas, their contribution to drug distribution in fetus, and their clinical significance.

Transcriptome Profiling of Placenta through Pregnancy Reveals Dysregulation of Bile Acids Transport and Detoxification Function

Placenta performs the function of several adult organs for the fetus during intrauterine life. Because of the dramatic physiological and metabolic changes during pregnancy and the strong association between maternal metabolism and placental function, the possibility that variation in gene expression patterns during pregnancy might be linked to fetal health warrants investigation. Here, next-generation RNA sequencing was used to investigate the expression profile, including mRNAs and long non-coding RNAs (lncRNAs) of placentas on day 60 of gestation (G60), day 90 of gestation (G90), and on the farrowing day (L0) in pregnant swine. Bioinformatics analysis of differentially expressed mRNAs and lncRNAs consistently showed dysregulation of bile acids transport and detoxification as pregnancy progress. We found the differentially expressed mRNAs, particularly bile salt export pump (ABCB11), organic anion-transporting polypeptide 1A2 (OATP1A2), carbonic anhydrase II (CA2), Na⁺-HCO₃⁻ cotransporter (NBC1), and hydroxysteroid sulfotransferases (SULT2A1) play an important role in bile acids transport and sulfation in placentas during pregnancy. We also found the potential regulation role of ALDBSSCG0000000220 and XLOC_1301271 on placental SULT2A1. These findings have uncovered a previously unclear function and its genetic basis for bile acids metabolism in developing placentas and have important implications for exploring the potential physiological and pathological pathway to improve fetal outcomes.

Targeted metabolomics analysis of maternal-placental-fetal metabolism in pregnant swine reveals links in fetal bile acid homeostasis and sulfation capacity

Cholestasis of pregnancy endangers fetal and neonatal survival, yet systematic knowledge of the cause and effect of disrupted bile acid (BA) homeostasis in pregnancy is limited. Here we show that gestation stage-associated BA dysregulation in swine correlated with fetal death resulting from compromised capacity for BA secretion and increased alternative systemic efflux. The balance of BA input and output in the developing uterus suggested little uptake and metabolism of maternal BA by the placenta-fetus unit, implying a protection role of placenta in preventing maternal BA transported into the fetus. We showed that the maternal origin of BA accounted for the increase in placental total BA, leading to dysregulated expression of genes involved in BA transport and potentially impaired transplacental export of fetus-derived BA. Correspondingly, the secondary BA, mainly derived from the mother, gradually decreased in the fetus. Finally, we identified that sulfation rather than glucuronidation played pivotal roles in maintaining BA homeostasis of the developing fetus. These novel and systemic findings contribute to a whole picture of BA metabolism in pregnancy and provide new insights into mechanisms responsible for maternal and fetal BA homeostasis. NEW & NOTEWORTHY We used a swine model to demonstrate the potentially impaired transplacental bile acid (BA) export, immaturity of fetal hepatic excretory function, and elevated BA synthesis in the developing fetus. Under these conditions, we have further identified that BA sulfation plays a pivotal role in regulation of fetal BA homeostasis, which appears to depend on the balance of BA synthesis and sulfation capacity. These novel findings have uncovered a previously unknown mechanism of BA homeostasis regulation in the developing fetus.

Characteristics of bile acids metabolism profile in the second and third trimesters of normal pregnancy

PURPOSE

Bile acids are a group of cholesterol metabolites functioning as key regulators of glucose, lipid, and energy metabolism. Their homeostatic control is essential to the physiology of the normal pregnancy. Abnormalities of bile acids regulation in pregnancy lead to intrahepatic cholestasis of pregnancy, a serious condition associated with a number of fetal and maternal morbidities. Dysregulation of glucose and lipids is also tied to perturbations in bile acid concentrations. Changes in bile acid metabolic profiles in the second and third trimesters of pregnancy have been incompletely explored. We seek to establish pregnancy-specific normative ranges for a number of bile acids in women in the second and third trimesters and explore changes in their concentrations in the period from 12 to 40 weeks gestation.

PROCEDURE

In this cross-sectional study, a total of 782 normal pregnant women were enrolled including n = 290 in the second trimester (12-28 weeks) and n = 492 in the third trimester (29-40 weeks). The concentrations of 14 bile acids were measured by liquid chromatography and mass spectrometry (LC-MS) and compared at various time points. Reference intervals of these bile acids were calculated using standard statistical techniques.

RESULTS

A reference interval profile of 14 bile acids from a cohort of 782 normal pregnant women was developed. Significant differences in concentration were found between the second trimester and the third trimester. Unconjugated bile acids dominate the bile acid profile in the second trimester, while conjugated bile acids, especially (taurine-conjugated) dominate in the third trimester. 28-31 weeks gestation was the notable change period of bile acid metabolism.

CONCLUSION

This study establishes pregnancy-specific reference intervals for bile acids in the second and third trimesters. As bile acid composition changes with gestational age, this study establishes a foundation for trimester-specific clinical interpretation of bile acid metabolic profiles in pregnant women.

Ursodeoxycholic acid inhibits uptake and vasoconstrictor effects of taurocholate in human placenta

Intrahepatic cholestasis of pregnancy (ICP) causes increased transfer of maternal bile acids to the fetus and an increased incidence of sudden fetal death. Treatment includes ursodeoxycholic acid (UDCA), but it is not clear if UDCA protects the fetus. This study explores the placental transport of the bile acid taurocholate (TC) by the organic anion-transporting polypeptide, (OATP)4A1, its effects on the placental proteome and vascular function, and how these are modified by UDCA. Various methodological approaches including placental villous fragments and Xenopus laevis oocytes were used to investigate UDCA transport. Placental perfusions and myography investigated the effect of TC on vasculature. The effects of acute TC exposure on placental tissue were investigated using quantitative proteomics. UDCA inhibited OATP4A1 activity in placental villous fragments and oocytes. TC induced vasoconstriction in placental and rat vasculature, which was attenuated by UDCA. Quantitative proteomic analysis of villous fragments showed direct effects of TC on multiple placental pathways, including oxidative stress and autophagy. The effects of TC on the placental proteome and vasculature demonstrate how bile acids may cause fetal distress in ICP. UDCA inhibition of OATP4A1 suggests it will protect the mother and fetus against the vascular effects of TC by inhibiting its cellular uptake. UDCA may protect the fetus in ICP by inhibiting OATP4A1-mediated bile acid transfer and TC-induced placental vasoconstriction. Understanding the physiologic mechanisms of UDCA may allow better therapeutic interventions to be designed specifically for the fetus in the future.-Lofthouse, E. M., Torrens, C., Manousopoulou, A., Nahar, M., Cleal, J. K., O'Kelly, I. M., Sengers, B. G., Garbis, S. D., Lewis, R. M. Ursodeoxycholic acid inhibits uptake and vasoconstrictor effects of taurocholate in human placenta.

May circulating steroids reveal a predisposition to intrahepatic cholestasis of pregnancy in non-pregnant women?

Intrahepatic cholestasis of pregnancy (ICP) is a frequent liver disorder, mostly occurring in the third trimester. ICP is not harmful to the mothers but threatens the fetus. The authors evaluated steroid alterations in maternal and mixed umbilical blood to elucidate their role in the ICP development. Ten women with ICP were included in the study. Steroids in the maternal blood were measured by Gas Chromatography-Mass Spectrometry (GC-MS) (n=58) and RIA (n=5) at the diagnosis of ICP, labor, day 5 postpartum, week 3 postpartum and week 6 postpartum. The results were evaluated by ANOVA consisting of the subject factor, between subject factors ICP, gestational age at the diagnosis of ICP and gestational age at labor, within-subject factor Stage and ICP × Stage interaction. The 17 controls were firstly examined in the week 36 of gestation. ICP patients showed reduced CYP17A1 activity in the C17,20 lyase step thus shifting the balance between the toxic conjugated pregnanediols and harmless sulfated 5alpha/beta-reduced-17-oxo C19 steroids. Hence, more toxic metabolites originating in maternal liver from the placental pregnanes may penetrate backward to the fetal circulation. As these alterations persist in puerperium, the circulating steroids could be potentially used for predicting the predisposition to ICP even before next pregnancy.

Role of bile acids in colon carcinogenesis

Bile acids (BAs) are cholesterol derivatives synthesized in the liver and then secreted into the intestine for lipid absorption. There are numerous scientific reports describing BAs, especially secondary BAs, as strong carcinogens or promoters of colon cancers. Firstly, BAs act as strong stimulators of colorectal cancer (CRC) initiation by damaging colonic epithelial cells, and inducing reactive oxygen species production, genomic destabilization, apoptosis resistance, and cancer stem cells-like formation. Consequently, BAs promote CRC progression via multiple mechanisms, including inhibiting apoptosis, enhancing cancer cell proliferation, invasion, and angiogenesis. There are diverse signals involved in the carcinogenesis mechanism of BAs, with a major role of epidermal growth factor receptor, and its down-stream signaling, involving mitogen-activated protein kinase, phosphoinositide 3-kinase/Akt, and nuclear factor kappa-light-chain-enhancer of activated B cells. BAs regulate numerous genes including the human leukocyte antigen class I gene, p53, matrix metalloprotease, urokinase plasminogen activator receptor, Cyclin D1, cyclooxygenase-2, interleukin-8, and miRNAs of CRC cells, leading to CRC promotion. These evidence suggests that targeting BAs is an efficacious strategies for CRC prevention and treatment.

Role of the placenta in serum autotaxin elevation during maternal cholestasis

Intrahepatic cholestasis of pregnancy (ICP) is frequently accompanied by pruritus, whose etiology has been associated with an enhanced production of lysophosphatidic acid (LPA) by the combined action of phospholipase A1/A2 (PLA1/PLA2) and autotaxin (ATX). Here, we have investigated whether the placenta is involved in LPA release to maternal circulation during ICP. Serum levels of ATX and LPA (determined by ELISA) were elevated in women with ICP, and a correlation between both parameters was found. No relationship between serum levels of ATX or LPA and bile acids was found. Expression levels of ATX and PLA2 were determined by RT-qPCR and Western blot. Placenta ATX but not PLA2 was significantly upregulated in ICP, and a tendency to increase was found at the protein level. A correlation between serum ATX and placental ATX mRNA levels was found. In human placenta at term, ATX was clearly detected (by immunofluorescence) in Hofbauer cells, but only faintly in trophoblast cells. In pregnant rats, the expression of Atx and Pla2 in placenta was lower than in liver. When obstructive cholestasis was imposed by bile duct ligation from day 14 of gestation until term, placenta Atx and Pla2 expression was markedly enhanced, and overexpression was confirmed at the protein level for Pla2, whereas Atx protein was not detected. In conclusion, the placenta substantially participates in LPA production during gestation. This contribution is markedly higher during maternal cholestasis and hence, may be involved in ICP-associated pruritus. NEW & NOTEWORTHY Fetal placental macrophages and, to a lesser extent, trophoblast cells express high levels of autotaxin at term. An increased expression of mRNA and protein autotaxin, the key secretory enzyme responsible for the production of lysophosphatidic acid in serum, has been observed in placentas of women with cholestasis of pregnancy, which supports that the placenta can contribute to an increased production of this pruritogenic compound in women suffering from this liver disease.

Ursodeoxycholate Restores Biliary Excretion of Methotrexate in Rats with Ethinyl Estradiol Induced-Cholestasis by Restoring Canalicular Mrp2 Expression

The in vivo relevance of ursodeoxycholate (UDCA) treatment (100 mg/kg/day, per oral tid for 5 days before cholestasis induction followed by the same dosing for 5 days) on hepatic function was investigated in rats with 17α-ethinylestradiol (EE, 10 mg/kg, subcutaneous for 5 days)-induced experimental cholestasis. The bile flow rate and the expression level of hepatic multidrug resistance-associated protein 2 (Mrp 2) that were decreased in cholestasis were restored after UDCA treatment. Consistent with this, the biliary excretion clearance (CL_exc,bile) of a representative Mrp2 substrate—methotrexate (MTX)—was decreased in cholestatic rats but was restored after UDCA treatment. Consequently, the plasma concentrations of MTX, which were increased by cholestasis, were decreased to control levels by UDCA treatment. Thus, the restoration of CL_exc,bile appears to be associated with the increase in Mrp2 expression on the canalicular membrane by UDCA treatment followed by Mrp2-mediated biliary excretion of MTX. On the other hand, the hepatic uptake clearance (CL_up,liver) of MTX was unchanged by cholestasis or UDCA treatment, suggestive of the absence of any association between the uptake process and the overall biliary excretion of MTX. Since UDCA has been known to induce the expression of canalicular MRP2 in humans, UDCA treatment might be effective in humans to maintain or accelerate the hepatobiliary elimination of xenobiotics or metabolic conjugates that are MRP2 substrates.

Effect of Intrahepatic Cholestasis of Pregnancy on Neonatal Birth Weight: A Meta-Analysis

OBJECTIVE

To evaluate the effect of intrahepatic cholestasis of pregnancy (ICP) on neonatal birth weight.

METHODS

Potential articles were identified by searching PubMed and Web of Science databases on April 30th, 2017. Using the Mantel-Haenszel random-effects or fixed-effects model, outcomes were summarized through weighted mean difference (WMD) and 95% confidence intervals (CI). Potential publication bias was tested using a funnel plot and the methods of Egger's regression and Begg's test.

RESULTS

A total of eight studies were included in our meta-analysis. Six studies reported data on neonatal birth weight in ICP and control pregnancies. Pooled data from the six studies showed that the birth weight in the ICP group was significantly lighter than in the control group. The overall pooled WMD was -175 g (95% CI: -301, -48). Meanwhile, pooled data from the other two studies indicated that the birth weight in the late-onset ICP group was heavier than in the early-onset ICP group (WMD: 267 g, 95% CI: 168, 366).

CONCLUSION

Neonatal birth weights in ICP pregnancies were lower than in normal pregnancies. Furthermore, early-onset ICP is associated with a lower birth weight than late-onset ICP.

Lactation during cholestasis: Role of ABC proteins in bile acid traffic across the mammary gland

Transporters involved in bile acid (BA) handling by the mammary gland are poorly understood. Here we have investigated the role of ABC proteins in blood-milk BA traffic and its sensitivity to maternal cholestasis. BA concentrations in rat and mouse serum were higher than in milk. BA profiles in both fluids were also different. In mammary gland, mRNA levels of ABC pumps transporting BAs were high for Bcrp, less abundant for Mrp1, Mrp3 and Mrp4 and negligible for Bsep and Mrp2. Milk BA concentrations were lower in Abcg2 ^-/- than in wild-type mice. Taurocholate administration (5 µmol, i.p.) increased 20-fold BA concentrations in serum, but only moderately in milk, even in Abcg2 ^-/- mice. Bile duct ligation (BDL) in pregnant rats markedly increased serum BA concentrations, which was not proportionally reflected in milk. In rat mammary tissue, Mrp4 was up-regulated by BDL. Serum BA levels were 2-fold higher in 10-day-old neonates of the BDL group, whereas their body weight was lower. The exchange of breastfeeding mothers immediately after birth reverted the situation without changes in endogenous BA synthesis. In conclusion, Bcrp is involved in BA secretion into milk, whereas Mrp4 participates in a blood-milk barrier that protects neonates from maternal hypercholanemia during breastfeeding.

Pregnancy and bile acid disorders

During pregnancy, extensive adaptations in maternal metabolic and immunological physiology occur. Consequently, preexisting disease may be exacerbated or attenuated, and new disease susceptibility may be unmasked. Cholestatic diseases, characterized by a supraphysiological raise in bile acid levels, require careful monitoring during pregnancy. This review describes the latest advances in the knowledge of intrahepatic cholestasis of pregnancy (ICP), the most common bile acid disorder specific to pregnancy, with a focus on the disease etiology and potential mechanisms of ICP-associated adverse pregnancy outcomes, including fetal demise. The course of preexisting cholestatic conditions in pregnancy is considered, including primary sclerosing cholangitis, primary biliary cholangitis, biliary atresia, and Alagille syndrome. The currently accepted treatments for cholestasis in pregnancy and promising new therapeutics for the condition are described.

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.

Relationship between early onset severe intrahepatic cholestasis of pregnancy and higher risk of meconium-stained fluid

Background

Intrahepatic cholestasis of pregnancy (ICP) is the commonest gestational liver disease. The risk of adverse fetal outcome has been associated with the severity of maternal hypercholanemia after diagnosis.

Objective

To investigate whether there is a relationship between the severity and timing of onset of hypercholanemia and the risk of meconium-stained amniotic fluid (MSAF) and adverse neonatal events.

Study design

The study included 382 pregnancies complicated by ICP managed at a referral hospital in Buenos Aires (Argentina) between June 2009 and December 2013. The patients were classified into three groups according to the severity of hypercholanemia at diagnosis; mild (10–19.9 μmol/L), moderate (20–39.9 μmol/L) and severe (≥40 μmol/L). Their clinical characteristics and pregnancy outcomes were investigated in a prospective observational study.

Results

Higher risk of MSAF was observed when ICP appeared early in gestation or when hypercholanemia was more severe. Taking both parameters into account an MSAF risk factor (MRF) was defined. Based on a model of positive/negative predictive values, a cut-off point of MRF = 3 was selected, which prioritized sensitivity versus specificity. In ICP patients with MRF>3, the probability of MSAF was enhanced 4-fold. An increase in the frequency of MSAF was also associated with higher serum levels at diagnosis of alanine transaminase, alkaline phosphatase and direct bilirubin.

Conclusions

The risk of MSAF is associated not only with the magnitude of hypercholanemia at diagnosis but also with the early gestational onset of raised maternal serum bile acids.

Evaluating the effectiveness and safety of ursodeoxycholic acid in treatment of intrahepatic cholestasis of pregnancy: A meta-analysis (a prisma-compliant study)

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is a specific pregnancy-related disorder without standard medical therapies. Ursodeoxycholic acid (UDCA) is the most used medicine, but the efficacy and safety of UDCA remain uncertain. Several meta-analyses had been made to assess the effects of UDCA in ICP. However, the samples were not large enough to convince obstetricians to use UDCA. We conducted a meta-analysis to evaluate the effects and safety of UDCA in patients with ICP, which included only randomized controlled trials (RCTs).

METHODS

Six databases were searched. The search terms were "ursodeoxycholicacid," "therapy," "management," "treatment," "intrahepatic cholestasis of pregnancy," "obstetric cholestasis," "recurrent jaundice of pregnancy," "pruritus gravidarum," "idiopathic jaundice of pregnancy," "intrahepatic jaundice of pregnancy," and "icterus gravidarum."Randomized controlled trials of UDCA versus control groups (included using other medicines) among patients with ICP were included. The primary outcomes were improved pruritus scores and liver function. Secondary outcomes were the maternal and fetal outcomes in patients with ICP.Data were extracted from included RCTs. The Mantel-Haenzel random-effects model or fixed-effects model was used for meta-analysis.

RESULTS

A total of 12 RCTs involving 662 patients were included in the meta-analysis. In pooled analyses that compared UDCA with all controls, UDCA was associated with resolution of pruritus (risk ratio [RR], 1.68; 95% confidence interval [CI],1.12-2.52; P = 0.01),decrease of serum levels of alanine aminotransferase (ALT) (standardized mean difference (SMD), -1.36; 95% CI, -2.08 to -0.63; P <0.001), reduced serum levels of bile acid (SMD, -0.68; 95% CI, -1.15 to -0.20; P <0.001), fewer premature births (RR, 0.56; 95% CI, 0.43-0.72; P <0.001),reduced fetal distress (RR, 0.68; 95% CI, 0.49-0.94; P = 0.02), high Apgar scores at 5 minutes (RR, 0.44; 95% CI, 0.24-0.82; P = 0.009), less frequent respiratory distress syndrome (RDS) (RR, 0.33; 95% CI, 0.13-0.86; P = 0.02), and fewer neonates in the intensive care unit (NICU) (RR, 0.55; 95% CI, 0.35-0.87; P <0.05), increased gestational age (SMD,0.44; 95% CI, 0.26-0.63; P <0.001), and birth weight (SMD, 0.21; 95% CI, 0.02-0.40; P = 0.03). There were no differences in meconium staining and intrauterine growth retardation (IUGR) between the groups (P >0.05). No trials reported adverse effects on mothers and fetuses except nausea and emesis.

CONCLUSION

UDCA is effective and safe to improve pruritus and liver function in ICP. UDCA also reduced adverse maternal and fetal outcomes in pregnant women with ICP.

Bile acids evoke placental inflammation by activating Gpbar1/NF-κB pathway in intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a cholestatic disorder with potentially deleterious consequences for fetuses. Although a clear correlation between the elevated levels of maternal serum bile acids and deficient fetal outcome has been established in clinical practice, the underlying mechanisms remain elusive. Herein, we report that bile acids induce NF-κB pathway activation via G protein-coupled bile acid receptor 1 (Gpbar1), with consequent upregulation of inflammatory genes in trophoblasts, leading to aberrant leukocyte infiltration and inflammation in placenta. Ursodeoxycholic acid (UDCA), a drug used clinically to treat ICP, competes with other bile acids for binding with Gpbar1 and thus inhibits bile acid-induced inflammatory response in trophoblasts and improves fetal survival in pregnant rats with obstructive cholestasis. Notably, inhibition of NF-κB by andrographolide is more effective than UDCA in benefiting placentas and fetuses. Thus, anti-inflammation therapy targeting Gpbar1/NF-κB pathway could be effective in suppressing bile acid-induced inflammation and alleviating ICP-associated fetal disorders.

Immunology of hepatic diseases during pregnancy

The mother's immune system has to adapt to pregnancy accepting the semi-allograft fetus and preventing harmful effects to the developing child. Aberrations in feto-maternal immune adaptation may result in disease of the mother, such as liver injury. Five pregnancy-associated liver disorders have been described so far, however, little is known concerning immune alterations promoting the respective disease. These liver disorders are pre-eclampsia, hemolysis, elevated liver enzymes, low platelet count (HELLP), acute fatty liver, hyperemesis gravidarum, and intrahepatic cholestasis of pregnancy. On the other hand, pre-existing autoimmune liver injury of the mother can be affected by pregnancy. This review intends to summarize current knowledge linking feto-maternal immunology and liver inflammation with a special emphasis on novel potential biomarkers.

Intrahepatic cholestasis of pregnancy: Recent advances

Intrahepatic cholestasis of pregnancy, also known as obstetric cholestasis, is a pruritic condition of pregnancy characterized by an underlying elevation in circulating bile acids and liver derangement, and associated with adverse fetal outcomes, such as preterm labor and stillbirth. Limited understanding of the underlying pathophysiology and mechanisms involved in adverse outcomes has previously restricted treatment options and pregnancy management. Recent advances in these research fields provide tantalizing targets to improve the care of pregnant women affected by this condition.

New Insights on Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is characterized by maternal pruritus, and elevated serum transaminases and bile acids. Genetic defects in at least 6 canalicular transporters have been found. Association studies stress the variability of genotypes, different penetrance, and influence of environmental factors. Serum autotaxin is a sensitive, specific, and robust diagnostic marker. Elevated maternal bile acids correlate with fetal complications. Long-term sequelae for mothers include the gallstone risk and chronic liver disease. There is an association between ICP and hepatitis C. Current treatment is ursodeoxycholic acid, owing to benefits on pruritus, liver function, safety, and decreased rates of adverse effects.

Immunological basis in the pathogenesis of intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy poses a great risk to both maternal and fetal health. Despite extensive research, much of the pathogenesis of this disorder is unknown. The increase in bile acids observed in patients with intrahepatic cholestasis of pregnancy has been noted to cause a change in the immune system from the normally mediated TH2 response to one that is more oriented towards TH1. In this literature review, we have critically reviewed the current literature regarding the changes in the immune system and the potential effects of immunological changes in the management of the patient. The current treatment, ursodeoxycholic acid, is also discussed along with potential combination therapies and future directions for research.