The pathophysiology of intrahepatic cholestasis of pregnancy

The Pathological Mechanisms of Estrogen-Induced Cholestasis: Current Perspectives

Estrogens are steroid hormones with a wide range of biological activities. The excess of estrogens can lead to decreased bile flow, toxic bile acid (BA) accumulation, subsequently causing intrahepatic cholestasis. Estrogen-induced cholestasis (EIC) may have increased incidence during pregnancy, and within women taking oral contraception and postmenopausal hormone replacement therapy, and result in liver injury, preterm birth, meconium-stained amniotic fluid, and intrauterine fetal death in pregnant women. The main pathogenic mechanisms of EIC may include deregulation of BA synthetic or metabolic enzymes, and BA transporters. In addition, impaired cell membrane fluidity, inflammatory responses and change of hepatocyte tight junctions are also involved in the pathogenesis of EIC. In this article, we review the role of estrogens in intrahepatic cholestasis, and outlined the mechanisms of EIC, providing a greater understanding of this disease.

Liver pathology in pregnancy

Liver dysfunction occurs in up to 3% of pregnancies and can be due to pregnancy-associated liver injury, exacerbation of pre-existing liver disease, or co-incident with pregnancy. The most common form of pregnancy-associated liver injury is intrahepatic cholestasis of pregnancy (ICP). This condition is typically benign and self-limited, but is associated with fetal morbidity and mortality with high levels of serum bile acids. Acute fatty liver of pregnancy (AFLP) and the hypertensive disorders of pregnancy (including pre-eclampsia, eclampsia, and hemolysis, elevated liver enzymes, and low platelets [HELLP] syndrome) are more commonly associated with maternal and fetal complications and may necessitate expedient delivery. Histologically, ICP shows nonspecific features of cholestasis, while AFLP and the hypertensive disorders have more characteristic histologic findings. While not a true liver disease, hyperemesis gravidarum can cause elevated liver enzymes. Pregnant patients are at increased risk of developing severe hepatitis E and herpesvirus infections, Budd-Chiari syndrome, and gallstones, and they may also experience worsening of known chronic liver disease. Mass lesions in pregnancy including hemangiomas, focal nodular hyperplasia, and hepatocellular adenomas and carcinomas can present unique challenges for diagnosis and management. This review will explore the pathophysiology, presentation, histologic features, and management of these conditions.

In vitro functional rescue by ivacaftor of an ABCB11 variant involved in PFIC2 and intrahepatic cholestasis of pregnancy

Background

ABCB11 variations are responsible for a spectrum of rare liver diseases, including progressive familial intrahepatic cholestasis type 2 (PFIC2) and intrahepatic cholestasis of pregnancy (ICP). Current medical treatment of these conditions mostly relies on ursodeoxycholic acid with limited efficacy. We report on the in vitro study of the p.A257V missense variant of ABCB11 identified in a PFIC2 patient and in her mother who experienced ICP.

Results

The Ala257 residue is located outside the ATP-binding site of ABCB11. We show that the p.A257V variant of ABCB11 is correctly expressed at the canalicular membrane of HepG2 cells but that its function significantly decreased when studied in MDCK cells. This functional defect can be fully rescued by Ivacaftor.

Conclusion

Ivacaftor could be considered as a new pharmacological tool able to respond to an unmet medical need for patients with ICP and PFIC2 due to ABCB11 variations affecting ABCB11 function, even when the residue involved is not located in an ATP-binding site of ABCB11.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02125-4.

Evaluation of G-Protein-Coupled Bile Acid Receptor 1 (TGR5) Levels in Intrahepatic Cholestasis of Pregnancy

Background and objective Intrahepatic cholestasis of pregnancy (ICP) is the most common pregnancy-related liver disease. G-protein-coupled bile acid receptor 1 (TGR5) agonists might be beneficial in ICP treatment. In this study, we aimed to investigate the relationship of serum TGR5 levels with ICP and associated itching. Methods Sixty-three pregnant women diagnosed with ICP based on a serum bile acid level of >10 µmol/L (patient group) and 47 healthy pregnant women as a control group were included in the study. In the patient group, ursodeoxycholic acid (UDCA) therapy was given at a dose of 15 mg/kg from the time of diagnosis until the termination of pregnancy. Serum transaminase levels were measured at the beginning and within 15 days after the onset of treatment, and the dose was increased in patients who were unresponsive to treatment. Results Bile acid level was found to be between 10-39 µmol/L in 61.9% of the ICP patients, and it was ≥40 µmol/L in 38.1% of the patients. The majority of the patients responded well to the treatment with UDCA. The mean TGR5 level was significantly higher in the patient group compared to the control group (0.98 ±0.95 ng/mL vs. 0.74 ±0.23 ng/mL, p=0.032). In the patient group, TGR5 level showed negative correlations with age and red cell distribution width and a positive correlation with lactate dehydrogenase level and lymphocyte count. Conclusions Based on our findings, it can be suggested that TGR5 may have a role in the pathogenesis but has no impact on the prognosis of the condition.

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.

Metabolic characteristics of plasma bile acids in patients with intrahepatic cholestasis of pregnancy-mass spectrometric study

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) is one of the more common complications in the middle and late stages of pregnancy, which requires early detection and intervention.

OBJECTIVE

The aim of the study is to investigate the changes in the metabolic profile of bile acids (BAs) in plasma of pregnant women with ICP and to look biomarkers for the diagnosis and grading of ICP, and to explore the disease mechanism.

METHODS

The targeted metabolomics based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze plasma BAs.

RESULTS

Twenty-seven BAs can be quantified in all participants. Among them, 22 BAs were identified as differential BAs between ICP and control groups. Five BAs include 3β-CA, 3β-DCA, CDCA-3Gln, NCA, and Tβ-MCA, were found to be associated with ICP for the first time. Nine BAs include NCA, GCA, GCDCA, GHCA, GUDCA, HCA, TCA, TCDCA and THCA, can be used as possible ICP diagnostic biomarkers. Four BAs, i.e., GLCA, THCA, GHCA and TLCA-3S may be used as potential biomarkers for ICP grading.

CONCLUSION

There were significant differences in plasma BA profiles between ICP patients and the control. The BA profiles of mild ICP group and severe ICP group partially overlapped. Potential diagnostic and grading BA markers were identified. A significant characteristic of ICP group was the increase of conjugated BAs. A mechanism to sustain the equilibrium of BA metabolism and adaptive response has been developed in ICP patients to accelerate excretion and detoxification.

Value of Serum Glycocholic Acid and Total Bile Acids in Predicting Maternal and Perinatal Outcomes in Intrahepatic Cholestasis of Pregnancy

Objective

To see whether serum glycocholic acid (CG) and total bile acids (TBA) can predict maternal and perinatal outcomes in pregnant women with intrahepatic cholestasis (ICP).

Method

The observation group consisted of 80 women with ICP who were treated in our hospital, whereas the control group consisted of 50 ordinary women who were also treated at our hospital at the same time. The levels of CG and TBA in the two groups were determined independently, and the differences in poor perinatal outcomes were compared. Finally, the predictive diagnostic value of CG and TBA for poor perinatal outcomes in ICP mothers was displayed using the Spearman correlation between CG and TBA and Apgar. The maternal CG and TBA levels in the observation group were substantially higher than in the control group (P0.05). The observation group had more significant maternal-fetal discomfort, neonatal asphyxia, preterm birth, and perinatal death than the control group (P0.05). The risk of poor perinatal outcomes in ICP mothers rose when TBA and CG levels increased (P0.05). Apgar ratings were inversely associated with CG and TBA (r = −0.8251 and r = −0.5969, respectively, P0.05). The CG and TBA diagnostic AUCs for unfavorable perinatal outcomes in ICP mothers were (P0.05).

Conclusion

CG and TBA have a high diagnostic value for ICP and may better predict and identify poor prenatal outcomes. It is suitable for clinical use.

Redox-Dependent Effects in the Physiopathological Role of Bile Acids

Bile acids (BA) are recognized by their role in nutrient absorption. However, there is growing evidence that BA also have endocrine and metabolic functions. Besides, the steroidal-derived structure gives BA a toxic potential over the biological membrane. Thus, cholestatic disorders, characterized by elevated BA on the liver and serum, are a significant cause of liver transplant and extrahepatic complications, such as skeletal muscle, central nervous system (CNS), heart, and placenta. Further, the BA have an essential role in cellular damage, mediating processes such as membrane disruption, mitochondrial dysfunction, and the generation of reactive oxygen species (ROS) and oxidative stress. The purpose of this review is to describe the BA and their role on hepatic and extrahepatic complications in cholestatic diseases, focusing on the association between BA and the generation of oxidative stress that mediates tissue damage.

Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a rare but potentially serious complication of pregnancy, the main symptom of which is intense pruritus with elevated serum levels of bile acids. The elevated serum bile acid concentration is regarded as a predictor for poor perinatal outcome including intrauterine death. Ursodeoxycholic acid (UDCA) has become established as the treatment of choice in clinical management to achieve a significant improvement in symptoms and reduce the cholestasis. Pregnant women with severe intrahepatic cholestasis should always be managed in a perinatal centre with close interdisciplinary monitoring and treatment involving perinatologists and hepatologists to minimise the markedly increased perinatal morbidity and mortality as well as maternal symptoms.

Management of Intrahepatic Cholestasis of Pregnancy: Recommendations of the Working Group on Obstetrics and Prenatal Medicine - Section on Maternal Disorders

Intrahepatic cholestasis of pregnancy (ICP) is the most common liver disease specific to pregnancy. The cardinal symptom of pruritus and a concomitant elevated level of bile acids in the serum and/or alanine aminotransferase (ALT) are suggestive for the diagnosis. Overall, the maternal prognosis is good. The fetal outcome depends on the bile acid level. ICP is associated with increased risks for adverse perinatal outcomes, including preterm delivery, meconium-stained amniotic fluid, and stillbirth. Acute fetal asphyxia and not chronic uteroplacental dysfunction leads to stillbirth. Therefore, predictive fetal monitoring is not possible. While medication with ursodeoxycholic acid (UDCA) improves pruritus, it has not been shown to affect fetal outcome. The indication for induction of labour depends on bile acid levels and gestational age. There is a high risk of recurrence in subsequent pregnancies.

Common ABCB4 and ABCB11 Genotypes Are Associated with Idiopathic Chronic Cholestasis in Adults

INTRODUCTION

Pathogenic mutations in genes encoding the hepatocanalicular transporters ATP8B1, ABCB11 and ABCB4 are causative for progressive cholestatic liver disease in children. In adults, less severe variants such as the common ABCB4 c.711A>T polymorphism have been associated with intrahepatic cholestasis in pregnancy and elevated liver enzymes. Hence, our aim was to study the role of common polymorphisms in adult patients with chronic unexplained cholestasis.

METHODS

Screening of outpatients of two university hospitals identified a cohort of 94 patients with chronic cholestasis of unknown origin after thorough exclusion of other causes. Genotyping was performed using TaqMan assays, and frequencies for the ABCB4 rs2109505 (c.711A>T), rs1202283 (c.504T>C), ABCB11 rs2287622 (p.A444V) and rs497692 (c.3084A>G) variants of the study cohort were compared to a cohort of 254 healthy controls.

RESULTS

The dominating symptoms of the patients were pruritus and jaundice, though the majority of them did not report symptoms at inclusion. Advanced fibrosis or cirrhosis was present in 11 patients (11.7%) only. Genotyping revealed the presence of the ABCB4 c.711A>T risk variant in 79 patients (84%), a frequency that is significantly (p = 0.037) higher than that in controls (71%). The ABCB11 p.A444V variant was also more frequent in cholestatic patients (p = 0.042).

CONCLUSION

The common ABCB4 c.711A>T and ABCB11 p.A444V polymorphisms are more prevalent in adult patients with idiopathic cholestasis than in healthy controls and may therefore represent risk factors for the development of chronic cholestatic liver disease.

Triggers of benign recurrent intrahepatic cholestasis and its pathophysiology: a review of literature

Benign recurrent intrahepatic cholestasis (BRIC) is a rare genetic disorder that is characterized by episodes of cholestasis followed by complete resolution. The episodic nature of BRIC raises concerns about its possible trigger factors. Indeed, case reports of this orphan disease have associated BRIC to some triggers. In the absence of any reviews, we reviewed BRIC trigger factors and its pathophysiology. The study consisted of a systematic search for case reports using PubMed. Articles describing a clear case of BRIC associated with a trigger were included resulting in 22 articles that describe 35 patients. Infection was responsible for 54.3% of triggered episodes, followed by hormonal, drugs, and miscellaneous causes reporting as 30%, 10%, and 5.7% respectively. Females predominated with 62.9%. The longest episode ranged between 3 months to 2 years with a mean of 32.37 weeks. The mean age of the first episode was 14.28 ranging between 3 months to 48 years. Winter and autumn were the major seasons during which episodes happened. Hence, BRIC is potentially triggered by infection, which is most commonly a viral infection, hormonal disturbances as seen in oral contraceptive pills and pregnancy state, and less commonly by certain drugs and other causes. The appearance of cholestasis during the first two trimesters of pregnancy compared to intrahepatic cholestasis of pregnancy could help to differentiate between the two conditions. The possible mechanism of BRIC induction implicates a role of BSEP and ATP8B1. While estrogen, drugs, and cytokines are known to affect BSEP, less is known about their action on ATP8B1.

Post-pregnancy recurrent biliary colic with intraoperative diagnosis of limy bile syndrome

Introduction

Limy bile syndrome (LBS) is an unusual condition in which gallbladder and/or bile ducts are filled with paste-like radiopaque material with a high calcium carbonate content. It can be rarely associated with PTH disorder and hypercalcemia.

Presentation of case

A 35-year-old woman presented with epigastric and right hypochondrium pain since a few hours. Similar attacks occurred in the past months soon after a pregnancy with vaginal delivery. Laboratory findings were not significant. The abdominal ultrasound highlighted a micro-lithiasis of gallbladder without complications. Considering the recurrent biliary attacks, laparoscopic cholecystectomy was performed with intraoperative diagnosis of LBS. A subsequent endocrinological screening highlighted a normocalcemic hyperparathyroidism associated with Vitamin D deficiency, likely related to the recent pregnancy and not to LBS.

Discussion

LBS is a rare condition with not clear etiology, frequently associated with cholelithiasis, of which it shares clinical presentation and potential complications. Diagnosis of LBS is based on abdominal X-ray/computed tomography scan, or it could be an intraoperative finding. The gold standard treatment is represented by laparoscopic cholecystectomy. The pregnancy with its related cholestatic phenotype could facilitate the LBS manifestation. An endocrinological screening should be performed to rule out a concomitant calcium metabolism disorder.

Conclusion

Knowledge of this rare condition could help general surgeons handle it properly.

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LBS is a rare condition characterized by a gallbladder and/or bile ducts filled with a a high calcium carbonate content

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LBS could be an incidental finding during cholecistectomy or preoperative diagnosed by abdominal X-ray/CT scan

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The gold standard of treatment for LBS is laparoscopic cholecystectomy

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A postoperative endocrinological screening should be performed to rule out a concomitant calcium metabolism disorder

[Intrahepatic cholestasis of pregnancy]

Intrahepatic cholestasis of pregnancy (ICP) is the most frequent pregnancy-specific liver disease. It is characterized by pruritus and an accompanying elevation of serum bile acid concentrations and/or alanine aminotransferase (ALT), which are the key parameters in the diagnosis. Despite good maternal prognosis, elevated bile acid concentration in maternal blood is an influencing factor to advers fetal outcome. The ICP is associated with increased rates of preterm birth, neonatal unit admission and stillbirth. This is the result of acute fetal asphyxia as opposed to a chronic uteroplacental insufficiency. Reliable monitoring or predictive tools (e.g. cardiotocography (CTG) or ultrasound) that help to prevent advers events are yet to be explored. Medicinal treatment with ursodeoxycholic acid (UDCA) does not demonstrably reduce adverse perinatal outcomes but does improve pruritus and liver function test results. Bile acid concentrations and gestational age should be used as indications to determine delivery. There is a high risk of recurrence in subsequent pregnancies.

Role of ursodeoxycholic acid on maternal serum bile acids and perinatal outcomes in intrahepatic cholestasis of pregnancy

AIM

Intrahepatic cholestasis of pregnancy (ICP) is associated with safe maternal outcomes but perinatal outcomes have been variable. We assessed clinical factors and impact of bile acid levels on maternal and neonatal outcomes in ICP.

METHODS

Patients with ICP (defined as pruritus with serum bile acids ≥ 10 mmol/l) were included prospectively with an assessment of risk factors, modes of delivery as well as maternal and neonatal outcomes. Mild and severe ICP were diagnosed when serum bile acid was always <40 mmol/l and ≥40 mmol/l, respectively. Patients with gestational pruritus served as controls.

RESULTS

Out of 643 patients, 375 patients (mean age 29 ± 7.6 years, 45.8% primigravida) met inclusion criteria. Pregnancy-induced hypertension [PIH: 10.5%; odds ratio (OR): 4.8; 95% confidence interval (CI): 2.4-8.5; P = 0.0014], gestational diabetes (GDM: 12.5%; OR: 2.6; 95% CI: 2.3-4.1; P = 0.045) and spontaneous preterm labor (15.1%; OR: 2.5; 95% CI: 1.2-3.5; P = 0.040) were higher in patients with ICP. Ursodeoxycholic acid (UDCA) (median dose 900 mg; 600-1800 mg) ameliorated symptoms of cholestasis, bile acid levels and liver aminotransferases in 79% cases. When compared with patients with mild ICP, patients with severe ICP presented at a lower gestational period (26 vs. 32 weeks, P = 0.036), required frequent induction (12.5%; OR: 3.2; 95% CI: 2.1-5.6; P = 0.045) and had increased fetal distress (15%; OR: 1.9; 95% CI: 1.3-4.9; P = 0.048).Overall eight stillbirths were recorded.

CONCLUSION

Severe ICP is associated with a higher incidence of GDM and PIH, risk of pre-term labor, elective induction and stillbirths. UDCA remains a first-line agent in treating ICP.

Intrahepatic Cholestasis of Pregnancy and Associated Adverse Maternal and Fetal Outcomes: A Retrospective Case-Control Study

Objective

Intrahepatic cholestasis of pregnancy (ICP) is a common pregnancy-related liver disease and is associated with an increased risk of adverse neonatal outcomes. Ursodeoxycholic acid (UDCA) is the most effective treatment. This study was aimed at investigating the adverse outcomes of ICP and evaluating the effects of treatment with UDCA in patients with ICP.

Methods

We included 114 women with ICP and 3725 women without ICP (no-ICP group) who delivered in our hospital between September 2017 and August 2019. The prevalence of ICP in this study was 3.15%. We matched each woman with ICP to five controls. Of all the 114 women with ICP, 73 (64.04%) received UDCA while 41 (35.96%) did not. Logistic multivariate regression analysis was used to compare the adverse outcomes between those with ICP and matched controls as well as between those who received UDCA (UDCA group) and those who did not (non-UDCA group).

Results

Compared with controls, women with ICP were more likely to have preeclampsia (adjusted odds ratio, aOR = 16.74, 95% CI 5.29-52.98), cesarean section (aOR = 1.76, 95% CI 1.10-2.81), and preterm birth (aOR = 24.35, 95% CI 2.74-216.67). Administration of UDCA reduced the rate of preterm birth (1.37% vs. 14.63%, aOR = 0.10, 95% CI 0.01-0.90).

Conclusion

ICP increased the risk of preeclampsia, cesarean section, and preterm birth. UDCA could reduce the rate of preterm birth.

Lysyl oxidase like protein-2 (LOXL-2); a novel marker for prediction of intrahepatic cholestasis of pregnancy

OBJECTIVE

Lysyl oxidase like protein 2 (LOXL-2) is an enzyme that is involved in the development of hepatic fibrosis and bile duct epithelial injury in hepatic cholestasis. Our aim was to investigate maternal serum levels of LOXL-2 and their relationship with fasting total bile acid (FTBA) levels in patients with intrahepatic cholestasis of pregnancy (ICP).

MATERIALS AND METHODS

Thirty-five pregnant women with ICP and 35 healthy women with uncomplicated pregnancies as the control group, were included in this cross-sectional study. Maternal serum LOXL-2, FTBA and other liver function test levels were compared between the two groups. The predictive cutoff value for LOXL-2 level in ICP was specified.

RESULTS

Serum LOXL-2 levels were found to be higher in the ICP group compared to the control group (225.699 ± 142.453 vs. 127.731 ± 63.419 pg/mL, p = .001). There was a significant positive correlation between serum LOXL-2 levels and FTBA levels (r = 0.330, p = .003). The optimal cutoff point for LOXL-2 for identifying increased risk of ICP was found to be ≥102 pg/mL, for which the sensitivity and specificity were 96.87% and 48.57%, respectively (p < .001).

CONCLUSIONS

Maternal serum LOXL-2 levels were significantly higher in women with ICP. LOXL-2 may be both an initiating factor in the pathophysiology of ICP and a marker in the prediction. It may also be a target in terms of preventing strategies in ICP.

Intrahepatic cholestasis of pregnancy associated with azathioprine: A case series

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is characterised by otherwise unexplained maternal pruritus, increased serum bile acid concentration over 10 μmol/L and spontaneous relief of symptoms and liver abnormalities after delivery. It occurs most frequently during the third trimester and is usually not induced by medication. Besides, azathioprine is recommended as first-line immunosuppressant in patients with steroid-dependent inflammatory bowel disease and is allowed during pregnancy, in order to stabilize maternal disease.

METHODS

We reviewed all cases of ICP between 2010 and 2018 in two French perinatal centers.

RESULTS

We encountered eight pregnancies complicated by atypical ICP among patients treated with azathioprine. ICP associated with azathioprine appears to be biologically more severe and to occur earlier than "standard" ICP. Furthermore, clinical and biochemical abnormalities related to ICP disappear when azathioprine is discontinued. Azathioprine safety should be reconsidered and practitioners advised to discuss discontinuing this drug as soon as ICP diagnosis is established.

ABCB4 disease: Many faces of one gene deficiency

ATP-binding cassette (ABC) subfamily B member 4 (ABCB4), also known as multidrug resistance protein 3 (MDR3), encoded by ABCB4, is involved in biliary phospholipid secretion, protecting hepatobiliary system from deleterious detergent and lithogenic properties of the bile. ABCB4 mutations altering canalicular ABCB4 protein function and expression may have variable clinical presentation and predispose to several human liver diseases. Well-established phenotypes of ABCB4 deficit are: progressive familial intrahepatic cholestasis type 3, gallbladder disease 1 (syn. low phospholipid associated cholelithiasis syndrome), high ɣ-glutamyl transferase intrahepatic cholestasis of pregnancy, chronic cholangiopathy, and adult biliary fibrosis/cirrhosis. Moreover, ABCB4 aberrations may be involved in some cases of drug induced cholestasis, transient neonatal cholestasis, and parenteral nutrition-associated liver disease. Recently, genome-wide association studies have documented occurrence of malignant tumours, predominantly hepatobiliary malignancies, in patients with ABCB4/MDR3 deficit. The patient's age at the time of the first presentation of cholestatic disease, as well as the severity of liver disorder and response to treatment are related to the ABCB4 allelic status. Mutational analysis of ABCB4 in patients and their families should be considered in all individuals with cholestasis of unknown aetiology, regardless of age and/or time of onset of the first symptoms.

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.

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.

Detection of additional abnormalities or co-morbidities in women with suspected intrahepatic cholestasis of pregnancy

Background

Current guidelines recommend viral, autoimmune, coagulation and liver ultrasound testing in intrahepatic cholestasis of pregnancy to exclude alternative diagnoses.

Methods

Electronic health records were searched for investigations and diagnoses in women with raised bile acid concentrations (>10 µmol/L) between January 2016 and December 2017 at two UK maternity units.

Results

Five hundred and thirty-one women had a raised bile acid concentration (median (IQR): 18 (13-32 µmol/L)) at a median gestation of 35.1 (IQR 31.8-37.0) weeks. Out of 531 women, 250 (47.1%) had full virology, autoimmune and ultrasound tests, and 348 (65.5%) had coagulation performed. Positive hepatitis B and C results were previously known. No new Epstein-Barr virus, cytomegalovirus or hepatitis A diagnoses were made. There were 11 positive autoimmune results, but no new diagnoses. No woman had an unexplained prolonged prothrombin time. No ultrasound liver (n = 38) or gallbladder (n = 85) abnormalities were of acute clinical significance.

Conclusion

Intrahepatic cholestasis of pregnancy investigations provided no new diagnoses that influenced clinical management during pregnancy.

Structure and Function of Hepatobiliary ATP Binding Cassette Transporters

The liver is beyond any doubt the most important metabolic organ of the human body. This function requires an intensive crosstalk within liver cellular structures, but also with other organs. Membrane transport proteins are therefore of upmost importance as they represent the sensors and mediators that shuttle signals from outside to the inside of liver cells and/or vice versa. In this review, we summarize the known literature of liver transport proteins with a clear emphasis on functional and structural information on ATP binding cassette (ABC) transporters, which are expressed in the human liver. These primary active membrane transporters form one of the largest families of membrane proteins. In the liver, they play an essential role in for example bile formation or xenobiotic export. Our review provides a state of the art and comprehensive summary of the current knowledge of hepatobiliary ABC transporters. Clearly, our knowledge has improved with a breath-taking speed over the last few years and will expand further. Thus, this review will provide the status quo and will lay the foundation for new and exciting avenues in liver membrane transporter research.

Curbing Obesity from One Generation to Another: the Effects of Bariatric Surgery on the In Utero Environment and Beyond

Approximately 250,000 individuals seek bariatric surgery each year in the USA for the long-term resolution of obesity-related comorbidities. Greater than 80% of these individuals are women and approximately half are of child-bearing age. Although there are many positive metabolic benefits that are realized through surgical weight loss for both men and women, the various long-term hormonal, molecular, nutrient, and epigenetic changes following bariatric surgery have not been evaluated for the surgical recipient or in the context of pregnancy and the offspring. Pregnancy may be a vulnerable period of time for the bariatric surgery recipient, and thoughtful consideration of pregnancy management should be taken by health care providers and recipients alike. The purpose of this review is to explore potential etiologies of some of the gestation-specific outcomes for the mother and offspring.

Whole-exome sequencing reveals ANO8 as a genetic risk factor for intrahepatic cholestasis of pregnancy

Background

Intrahepatic cholestasis of pregnancy (ICP) is characterized by pruritus and cholestasis in late pregnancy and results in adverse pregnancy outcomes, including preterm delivery and birth weight, which are affected by the genetic and environmental background. However, until now, the genetic architecture of ICP has remained largely unclear.

Methods

Twenty-six clinical data points were recorded for 151 Chinese ICP patients. The data generated from whole-exome sequencing (WES) using the BGISEQ-500 platform were further analyzed by Burrows-Wheeler Aligner (BWA) software, Genome Analysis Toolkit (GATK), ANNOVAR tool, etc. R packages were used to conduct t-test, Fisher’s test and receiver operating characteristic (ROC) curve analyses.

Results

We identified eighteen possible pathogenic loci associated with ICP disease in known genes, covering ABCB4, ABCB11, ATP8B1 and TJP2. The loci Lys386Gln, Gly527Gln and Trp708Ter in ABCB4, Leu589Met, Gln605Pro and Gln1194Ter in ABCB11, and Arg189Ser in TJP2 were novel discoveries. In addition, WES analysis indicated that the gene ANO8 involved in the transport of bile salts is newly identified as associated with ICP. The functional network of the ANO8 gene confirmed this finding. ANO8 contained 8 rare missense mutations that were found in eight patients among the 151 cases and were absent from 1029 controls. Out of the eight SNPs, 3 were known, and the remaining five are newly identified. These variants have a low frequency, ranging from 0.000008 to 0.00001 in the ExAC, gnomAD – Genomes and TOPMED databases. Bioinformatics analysis showed that the sites and their corresponding amino acids were both highly conserved among vertebrates. Moreover, the influences of all the mutations on protein function were predicted to be damaging by the SIFT tool. Combining clinical data, it was found that the mutation group (93.36 µmol/L) had significantly (P = 0.038) higher total bile acid (TBA) levels than the wild-type group (40.81 µmol/L).

Conclusions

To the best of our knowledge, this is the first study to employ WES technology to detect genetic loci for ICP. Our results provide new insights into the genetic basis of ICP and will benefit the final identification of the underlying mutations.

Intrahepatic cholestasis of pregnancy: Is a screening for differential diagnoses necessary?

OBJECTIVE

To evaluate the benefit of performing a screening for differential diagnoses by hepatobiliary ultrasound and viral serologies, in case of suspected intrahepatic cholestasis of pregnancy (ICP).

METHODS

Retrospective single-center study in a tertiary maternity unit, including all women with a suspected ICP between January 2012 and September 2018. The primary outcome was the differential diagnosis rate obtained through initial screening. We described women characteristics, symptoms, and blood results that led to ICP suspicion. We evaluated the rate of differential diagnosis established by the initial screening. We described the population of women presenting with an ICP differential diagnosis.

RESULTS

The study included 254 women. Prevalence of differential diagnosis was 2 %. ICP was suspected in more than 50 % of cases in third trimester of pregnancy (79.5 %). Women presented with pruritus in 90.9 % of cases. Bile acid levels were between 20 and 40 μmol/L in 56.3 % of cases and above 40 μmol/L in 12.2 % of cases. The screening to rule out differential diagnosis of ICP was performed in half of the cases. When performed, the screening did not lead to the diagnosis of any differential disease.

CONCLUSION

In this cohort, among the 254 women, one (0.4 %) would have been wrongly diagnosed with ICP if the initial screening for differential diagnosis had not been performed. Screening for differential diagnosis does not seem to provide any benefit regarding the management of suspected ICP and could therefore only be performed in case of atypical clinical presentation of ICP, resistance to treatment or persisting abnormal liver function tests in the postpartum period.

Variants in ABCB4 (MDR3) across the spectrum of cholestatic liver diseases in adults

The ATP binding cassette subfamily B member 4 (ABCB4) gene on chromosome 7 encodes the ABCB4 protein (alias multidrug resistance protein 3 [MDR3]), a P-glycoprotein in the canalicular membrane of the hepatocytes that acts as a translocator of phospholipids into bile. Several variants in ABCB4 have been shown to cause ABCB4 deficiency, accounting for a disease spectrum ranging from progressive familial cholestasis type 3 to less severe conditions like low phospholipid-associated cholelithiasis, intrahepatic cholestasis of pregnancy or drug-induced liver injury. Furthermore, whole genome sequencing has shown that ABCB4 variants are associated with an increased incidence of gallstone disease, gallbladder and bile duct carcinoma, liver cirrhosis or elevated liver function tests. Diagnosis of ABCB4 deficiency-related diseases is based on clinical presentation, serum biomarkers, imaging techniques, liver histology and genetic testing. Nevertheless, the clinical presentation can vary widely and clear genotype-phenotype correlations are currently lacking. Ursodeoxycholic acid is the most commonly used medical treatment, but its efficacy has yet to be proven in large controlled clinical studies. Future pharmacological options may include stimulation/restoration of residual function by chaperones (e.g. 4-phenyl butyric acid, curcumin) or induction of ABCB4 transcription by FXR (farnesoid X receptor) agonists or PPARα (peroxisome proliferator-activated receptor-α)-ligands/fibrates. Orthotopic liver transplantation remains the last and often only therapeutic option in cirrhotic patients with end-stage liver disease or patients with intractable pruritus.

Obeticholic acid improves fetal bile acid profile in a mouse model of gestational hypercholanemia

Intrahepatic cholestasis of pregnancy (ICP) is characterized by elevated maternal circulating bile acid levels and associated dyslipidemia. ICP leads to accumulation of bile acids in the fetal compartment, and the elevated bile acid concentrations are associated with an increased risk of adverse fetal outcomes. The farnesoid X receptor agonist obeticholic acid (OCA) is efficient in the treatment of cholestatic conditions such as primary biliary cholangitis. We hypothesized that OCA administration during hypercholanemic pregnancy will improve maternal and fetal bile acid and lipid profiles. Female C57BL/6J mice were fed either a normal chow diet, a 0.5% cholic acid (CA)-supplemented diet, a 0.03% OCA-supplemented diet, or a 0.5% CA + 0.03% OCA-supplemented diet for 1 wk before mating and throughout pregnancy until euthanization on day 18. The effects of CA and OCA feeding on maternal and fetal morphometry, bile acid and lipid levels, and cecal microbiota were investigated. OCA administration during gestation did not alter the maternal or fetal body weight or organ morphometry. OCA treatment during hypercholanemic pregnancy reduced bile acid levels in the fetal compartment. However, fetal dyslipidemia was not reversed, and OCA did not impact maternal bile acid levels or dyslipidemia. In conclusion, OCA administration during gestation had no apparent detrimental impact on maternal or fetal morphometry and improved fetal hypercholanemia. Because high serum bile acid concentrations in ICP are associated with increased rates of adverse fetal outcomes, further investigations into the potential use of OCA during cholestatic gestation are warranted.NEW & NOTEWORTHY We used a mouse model of gestational hypercholanemia to investigate the use of obeticholic acid (OCA), a potent FXR agonist, as a treatment for the hypercholanemia of intrahepatic cholestasis of pregnancy (ICP). The results demonstrate that OCA can improve the fetal bile acid profile. This is relevant not only to women with ICP but also for women who become pregnant while receiving OCA treatment for other conditions such as primary biliary cholangitis and nonalcoholic steatohepatitis.

Intrahepatic Cholestasis in Pregnancy: Review of the Literature

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

Liver Diseases in the Perinatal Period: Interactions Between Mother and Infant

Liver diseases affecting the mother and infant dyad may present in the perinatal period from 20 weeks of gestation to 28 days of life. This review will focus on the current approach to neonatal acute liver failure and the progress made in the diagnosis and management of gestational alloimmune liver disease. It will highlight mother-to-child transmission of viral hepatitis, both management and public health implications. Emerging concepts implicating maternal obesity and nutrition in the development of a rapidly progressive nonalcoholic steatohepatitis phenotype in the offspring will be discussed. Finally, the presentation and management of acute fatty liver of pregnancy and intrahepatic cholestasis of pregnancy, and their impact on the fetus, will be reviewed.

Intrahepatic cholestasis of pregnancy as a risk factor for preeclampsia

PURPOSE

Intrahepatic cholestasis of pregnancy and preeclampsia are two major pregnancy complications. We aimed to investigate the association between intrahepatic cholestasis of pregnancy (ICP) and preeclampsia.

METHODS

Single-center retrospective study. Study group included 180 women (162 singletons and 18 twin gestations) who were diagnosed with ICP based on clinical presentation, elevated liver enzymes and bile acids. The reference group included 1618 women (1507 singletons and 111 twin gestations) who delivered during the study period, and were matched according to age, gravidity, parity and singleton or twin gestation.

RESULTS

The incidence of ICP was 0.36%. The incidence of preeclampsia was higher in women with ICP compared to reference group (7.78% vs 2.41%, aOR, 3.74 95% CI 12.0-7.02, p < 0.0001), for either without-(3.89% vs 1.61%, aOR 2.83, 95% CI 1.23-6.5, p = 0.145) or with severe features (3.89% vs 0.80%, aOR 5.17 95% CI 2.14-12.50, p = 0.0003). For both singleton and twin pregnancies, overall preeclampsia rates were higher in the ICP group (5.56% vs 2.19%, aOR 2.91 95% CI 1.39-6.07 p = 0.0045; and 27.78% vs 5.41%, aOR 10.9 95% CI 2.16-47.19, p = 0.0033, respectively). Earlier diagnosis of ICP was associated with higher incidence of preeclampsia (31.1 ± 3.8 vs 34.86 ± 6.2 gestational weeks, p = 0.0259). The average time between ICP diagnosis and to the onset of preeclampsia was 29.7 ± 24 days.

CONCLUSION

ICP is associated with an increased risk for preeclampsia. We suggest intensified follow-up for preeclampsia in women with ICP, especially among those with early ICP presentation and twins' gestations.

Unexplained First Trimester Intrahepatic Cholestasis of Pregnancy: A Case Report and Literature Review

Intrahepatic cholestasis of pregnancy (ICP) is a condition that usually affects the 3^rd trimester-pregnant women and is associated with adverse pregnancy outcomes. We present a 31-year-old G2P1 patient with symptoms of ICP as early as 10 weeks of gestation (WG). Her pruritis was initially attributed to eczema. Due to the intensity of her discomfort and failure of topical treatment, ICP was suspected, total bile acid salt levels were taken and ursodeoxycholic acid was subsequently started at 18 WG. The patient was followed closely during her pregnancy to adjust the dose of the medication accordingly. Induction of labor was performed at 37 WG without complications. This case demonstrated the importance of clinical suspicion in the setting of such symptomatology in order not to miss or delay treatment of threatening conditions such as ICP.

ABCB4/MDR3 in health and disease – at the crossroads of biochemistry and medicine

Several ABC transporters of the human liver are responsible for the secretion of bile salts, lipids and cholesterol. Their interplay protects the biliary tree from the harsh detergent activity of bile salts. Among these transporters, ABCB4 is essential for the translocation of phosphatidylcholine (PC) lipids from the inner to the outer leaflet of the canalicular membrane of hepatocytes. ABCB4 deficiency can result in altered PC to bile salt ratios, which led to intrahepatic cholestasis of pregnancy, low phospholipid associated cholelithiasis, drug induced liver injury or even progressive familial intrahepatic cholestasis type 3. Although PC lipids only account for 30–40% of the lipids in the canalicular membrane, 95% of all phospholipids in bile are PC lipids. We discuss this discrepancy in the light of PC synthesis and bile salts favoring certain lipids. Nevertheless, the in vivo extraction of PC lipids from the outer leaflet of the canalicular membrane by bile salts should be considered as a separate step in bile formation. Therefore, methods to characterize disease causing ABCB4 mutations should be considered carefully, but such an analysis represents a crucial point in understanding the currently unknown transport mechanism of this ABC transporter.

Enzymatic quantification of total serum bile acids as a monitoring strategy for women with intrahepatic cholestasis of pregnancy receiving ursodeoxycholic acid treatment: a cohort study

OBJECTIVE

To evaluate enzymatic total serum bile acid quantification as a monitoring strategy for women with intrahepatic cholestasis of pregnancy (ICP) treated with ursodeoxycholic acid (UDCA).

DESIGN

Cohort.

SETTING

One UK university hospital.

POPULATION

29 ICP cases treated with UDCA.

METHODS

Serial samples were collected prospectively throughout gestation. Total serum bile acids were measured enzymatically and individual bile acids by high-performance liquid chromatography-tandem mass spectrometry. Data were log-transformed and analysed with random effects generalised least square regression.

MAIN OUTCOME MEASURES

The relationship between enzymatic total bile acid measurements and individual bile acid concentrations after UDCA treatment.

RESULTS

In untreated women, cholic acid was the principal bile acid (51%) and UDCA concentrations were <0.5%, whereas UDCA constituted 60% (IQR 43-69) of serum bile acids following treatment and cholic acid fell to <20%. Changes in the total bile acid measurement reflected similar alterations in the concentrations of the pathologically elevated bile acids, e.g. a two-fold increase in enzymatic total bile acids is accompanied by approximately a two-fold increase in cholic acid and chenodeoxycholic acid at most UDCA doses (P < 0.001). Most of the effects of UDCA on cholic acid occur in the first week of treatment (60% relative reduction, P = 0.025, 95% CI 0.2-0.9, from 10 micromol/l (4.7-17.6) to 3.5 micromol/l (1.4-7.5).

CONCLUSION

Ursodeoxycholic acid becomes the main component of the bile acid measurement after treatment. Enzymatic total bile acid assays are good predictors of both cholic acid and chenodeoxycholic acid, the primary bile acids that are raised prior to treatment.

TWEETABLE ABSTRACT

Ursodeoxycholic acid constitutes approximately 60% of the bile acid measurement and reduces pathological cholic acid in treated women.

Women successfully treated for severe intrahepatic cholestasis of pregnancy do not have increased risks for adverse perinatal outcomes

Intrahepatic cholestasis of pregnancy (ICP) increases adverse perinatal outcome (APO) incidence. Whether successful treatment of severe ICP reduces APO risk is unclear.This retrospective, single-center study in China enrolled consecutive women with ICP who had term delivery (≥37 weeks, singleton) between August 2013 and June 2016. Patients were divided into the mild ICP (serum bile acids (SBA) ≤40 μmol/L throughout pregnancy) and severe ICP (SBA >40 μmol/L during pregnancy but fell after ursodeoxycholate therapy) groups. Baseline characteristics, laboratory investigations, and maternal and neonatal outcomes were assessed. Logistic regression was used to identify factors associated with meconium staining of amniotic fluid (MSAF) and APOs.Seventy-three patients were included (mild ICP group, n=47; severe ICP group, n=26). Pruritus was more common in the severe ICP group (65.4% vs 40.4%; P <.05), but other baseline characteristics were similar. Compared with the mild ICP group, the severe ICP group had higher SBA at first visit and peak value, higher direct bilirubin before delivery and 4 days postpartum, and lower gamma-glutamyltransferase at peak value, before delivery and 4 days postpartum (P <.05). Other laboratory parameters, type of delivery, hemorrhage, and liver function abnormality were similar between groups, although the severe ICP group had longer duration of hepatic dysfunction (P <.05). Birth weight was lower in the mild ICP group (P <.05), but other fetal outcomes were similar between groups. Logistic regression identified no factors (including SBA group) associated with APOs or MSAF.Women successfully treated for severe ICP do not have increased risks for APOs.

Relations of neuropeptide Y and heme oxygenase-1 expressions with fetal brain injury in rats with intrahepatic cholestasis of pregnancy

PURPOSE

To investigate the relations of neuropeptide Y (NPY) and heme oxygenase-1 (HO-1) expressions with fetal brain injury in rats with intrahepatic cholestasis of pregnancy (ICP).

METHODS

Sixty rats pregnant for 15 days were randomly divided into experimental and control groups. The ICP model was established in experimental group. On the 21st day, the blood biochemical test, histopathological examination of pregnant rat liver and fetal brain tissues and immunohistochemical analysis of fetal rat brain tissues were performed.

RESULTS

On the 21st day, the alanineaminotransferase, aspartate aminotransferase and total bile acid levels in experimental group were significantly higher than control group (P<0.01). Compared with control group, there was obvious vacuolar degeneration in pregnant rat liver tissue and fetal brain tissue in experimental group. NPY expression in fetal brain tissue was negative in control group and positive in experimental group. HO-1 expression in fetal brain tissue was strongly positive in control group and positive in experimental group. There was significant difference of immunohistochemical staining optical density between two groups (P<0.01).

CONCLUSION

In fetal brain of ICP rats, the NPY expression is increased, and the HO-1 expression is decreased, which may be related to the fetal brain injury.

Expanding etiology of progressive familial intrahepatic cholestasis

BACKGROUND

Progressive familial intrahepatic cholestasis (PFIC) refers to a disparate group of autosomal recessive disorders that are linked by the inability to appropriately form and excrete bile from hepatocytes, resulting in a hepatocellular form of cholestasis. While the diagnosis of such disorders had historically been based on pattern recognition of unremitting cholestasis without other identified molecular or anatomic cause, recent scientific advancements have uncovered multiple specific responsible proteins. The variety of identified defects has resulted in an ever-broadening phenotypic spectrum, ranging from traditional benign recurrent jaundice to progressive cholestasis and end-stage liver disease.

AIM

To review current data on defects in bile acid homeostasis, explore the expanding knowledge base of genetic based diseases in this field, and report disease characteristics and management.

METHODS

We conducted a systemic review according to PRISMA guidelines. We performed a Medline/PubMed search in February-March 2019 for relevant articles relating to the understanding, diagnosis, and management of bile acid homeostasis with a focus on the family of diseases collectively known as PFIC. English only articles were accessed in full. The manual search included references of retrieved articles. We extracted data on disease characteristics, associations with other diseases, and treatment. Data was summarized and presented in text, figure, and table format.

RESULTS

Genetic-based liver disease resulting in the inability to properly form and secrete bile constitute an important cause of morbidity and mortality in children and increasingly in adults. A growing number of PFIC have been described based on an expanded understanding of biliary transport mechanism defects and the development of a common phenotype.

CONCLUSION

We present a summary of current advances made in a number of areas relevant to both the classically described FIC1 (ATP8B1), BSEP (ABCB11), and MDR3 (ABCB4) transporter deficiencies, as well as more recently described gene mutations -- TJP2 (TJP2), FXR (NR1H4), MYO5B (MYO5B), and others which expand the etiology and understanding of PFIC-related cholestatic diseases and bile transport.

Bile Acids as Metabolic Regulators and Nutrient Sensors

Bile acids facilitate nutrient absorption and are endogenous ligands for nuclear receptors that regulate lipid and energy metabolism. The brain-gut-liver axis plays an essential role in maintaining overall glucose, bile acid, and immune homeostasis. Fasting and feeding transitions alter nutrient content in the gut, which influences bile acid composition and pool size. In turn, bile acid signaling controls lipid and glucose use and protection against inflammation. Altered bile acid metabolism resulting from gene mutations, high-fat diets, alcohol, or circadian disruption can contribute to cholestatic and inflammatory diseases, diabetes, and obesity. Bile acids and their derivatives are valuable therapeutic agents for treating these inflammatory metabolic diseases.

Association between bile salt export pump polymorphisms and intrahepatic cholestasis of pregnancy susceptibility: a meta-analysis of case-control studies

The purpose of this meta-analysis was to investigate the relationship between bile salt export pump (BSEP) polymorphisms and intrahepatic cholestasis of pregnancy (ICP) susceptibility. Retrieved studies from Pubmed, EMBASE, Web of Science, Cochrane Library and CBM databases about BSEP polymorphisms and ICP susceptibility were included. Odds ratio (OR) and 95% confidence interval (CI) and publication bias were calculated. Ten related case-control studies on BSEP polymorphisms and ICP susceptibility were included. The pooled results showed a significant association between BSEP rs2287622 polymorphism and ICP risk in Asian population (OR >1, p < .01 for A vs. a and AA vs. Aa/aa) and general population (OR >1, p < .05 for A vs. a, Aa vs. aa, AA/Aa vs. aa), and a borderline statistical significance was found between BSEP rs473351 polymorphism and ICP susceptibility (OR = 1.66, p < .05), and no statistical significance was found in D482G or rs853782 polymorphisms and ICP risk (all p > .05). Additionally, no publication bias was found in these studies (all p > .05). Our current meta-analysis indicated that BSEP rs2287622 polymorphism could increase the susceptibility of ICP in Asians and in general populations, while rs473351, D482G, and rs853782 polymorphisms were not obviously associated with ICP risk, but it needs further larger study with ethnicity and various etiologies.

The role of metabolic disorders in the pathogenesis of intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disorder which typically commences in the late second or third trimester and resolves within 48 hours after delivery. It is characterized by mild to severe pruritus, without any specific dermatologic features, elevated liver enzymes and increased serum bile acids (BA). The etiology of ICP is still not completely explicit. Pathogenesis includes a combination of hormonal and environmental factors superimposing on a genetic predisposition. During recent years increasingly ICP is recognized to be associated with an abnormal metabolic profile, including glucose intolerance and dyslipidemia, although it is considered to be secondary to maternal aberrant BA homeostasis. This article reviews the recent literature data and current concepts for ICP, with emphasis on a possibility of metabolic disorders being primary causative factors in ICP pathogenesis.

Intrahepatic Cholestasis of Pregnancy: A Review of Diagnosis and Management

Importance

Intrahepatic cholestasis of pregnancy (ICP) complicates approximately 0.2% to 2% of pregnancies and can lead to increased fetal risks in pregnancy.

Objective

This review aims to increase the knowledge of women's health care providers regarding the diagnosis, management, and fetal risks associated with ICP.

Results

The diagnosis of ICP is based on symptoms of pruritus that typically include the palms and soles, as well as elevated bile acid levels. Other liver function tests such as alanine aminotransferase and aspartate aminotransferase are also frequently elevated, and other causes of liver dysfunction should be ruled out. Fetal risks of ICP include increased risk of preterm birth, meconium-stained amniotic fluid, respiratory distress syndrome, or stillbirth. There is evidence that as bile acid levels increase, so does the risk of adverse neonatal outcomes. Ursodeoxycholic acid treatment has been shown to improve maternal pruritus symptoms, as well as biochemical tests, but no treatment has been shown to definitively improve fetal outcomes.

Conclusions and Relevance

Providers should be aware of the signs and symptoms of ICP and provide accurate diagnosis and management of affected women. Women with a diagnosis of ICP should be treated with ursodeoxycholic acid to improve maternal symptoms. Given the increased risk of stillbirth in the setting of ICP, delivery may be considered at 37 weeks' gestation.

New Insights in Genetic Cholestasis: From Molecular Mechanisms to Clinical Implications

Cholestasis is characterised by impaired bile secretion and accumulation of bile salts in the organism. Hereditary cholestasis is a heterogeneous group of rare autosomal recessive liver disorders, which are characterised by intrahepatic cholestasis, pruritus, and jaundice and caused by defects in genes related to the secretion and transport of bile salts and lipids. Phenotypic manifestation is highly variable, ranging from progressive familial intrahepatic cholestasis (PFIC)-with onset in early infancy and progression to end-stage liver disease-to a milder intermittent mostly nonprogressive form known as benign recurrent intrahepatic cholestasis (BRIC). Cases have been reported of initially benign episodic cholestasis that subsequently transitions to a persistent progressive form of the disease. Therefore, BRIC and PFIC seem to represent two extremes of a continuous spectrum of phenotypes that comprise one disease. Thus far, five representatives of PFIC (named PFIC1-5) caused by pathogenic mutations present in both alleles of ATP8B1, ABCB11, ABCB4, TJP2, and NR1H4 have been described. In addition to familial intrahepatic cholestasis, partial defects in ATP8B1, ABCB11, and ABCB4 predispose patients to drug-induced cholestasis and intrahepatic cholestasis in pregnancy. This review summarises the current knowledge of the clinical manifestations, genetics, and molecular mechanisms of these diseases and briefly outlines the therapeutic options, both conservative and invasive, with an outlook for future personalised therapeutic strategies.

Role of ischemia-modified albumin in the evaluation of oxidative stress in intrahepatic cholestasis of pregnancy

Objective: The objective of this study is to investigate the ischemia-modified albumin (IMA) level, and the IMA/albumin ratio (IMAR) in healthy pregnant women, and pregnant women with intrahepatic cholestasis of pregnancy (ICP). Material and method: This cross-sectional study included 53 women with ICP and 52 healthy pregnant women. Their serum IMA and albumin levels were analyzed, and the women were followed up to delivery. Results: No significant intergroup differences were identified in maternal age, body mass index, and gestational age at the time that the blood samples were taken. The gestational age at delivery and the serum albumin level was significantly lower (p = .002 and p < .0001, respectively) in the ICP group than in the healthy pregnant women. Although no differences in IMA levels were shown between the groups, IMA/albumin levels were higher in the ICP group than in the healthy pregnant women (p = .004). Conclusion: Serum IMA levels did not differ between pregnant women with ICP and healthy pregnant women, while the IMAR was significantly higher in the ICP group versus the healthy pregnant women.

[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.

Pruritus in Pregnancy and Its Management

Pruritus in pregnancy can be a source of significant discomfort in the pregnant patient. Some cases are associated with pregnancy-specific dermatoses, although some patients experience a flare of a preexisting dermatosis. Severe pruritus may be a manifestation of a pregnancy-specific dermatosis associated with increased fetal risks and complications. Early accurate diagnosis and appropriate management are important. Examination often reveals important clinical findings, aiding accurate diagnosis. Pemphigoid gestationis often presents with periumbilical involvement, whereas polymorphic eruption of pregnancy spares the umbilicus and presents in the striae distensae. Intrahepatic cholestasis of pregnancy is associated with intense pruritus of the palms.

Sequencing of FIC1, BSEP and MDR3 in a large cohort of patients with cholestasis revealed a high number of different genetic variants

BACKGROUND & AIMS

The bile salt export pump (BSEP, ABCB11), multidrug resistance protein 3 (MDR3, ABCB4) and the ATPase familial intrahepatic cholestasis 1 (FIC1, ATP8B1) mediate bile formation. This study aimed to determine the contribution of mutations and common variants in the FIC1, BSEP and MDR3 genes to cholestatic disorders of differing disease onset and severity.

METHODS

Coding exons with flanking intron regions of ATP8B1, ABCB11, and ABCB4 were sequenced in cholestatic patients with assumed genetic cause. The effects of new variants were evaluated by bioinformatic tools and 3D protein modeling.

RESULTS

In 427 patients with suspected inherited cholestasis, 149 patients carried at least one disease-causing mutation in FIC1, BSEP or MDR3, respectively. Overall, 154 different mutations were identified, of which 25 were novel. All 13 novel missense mutations were disease-causing according to bioinformatics analyses and homology modeling. Eighty-two percent of patients with at least one disease-causing mutation in either of the three genes were children. One or more common polymorphism(s) were found in FIC1 in 35.3%, BSEP in 64.3% and MDR3 in 72.6% of patients without disease-causing mutations in the respective gene. Minor allele frequencies of common polymorphisms in BSEP and MDR3 varied in our cohort compared to the general population, as described by gnomAD. However, differences in ethnic background may contribute to this effect.

CONCLUSIONS

In a large cohort of patients, 154 different variants were detected in FIC1, BSEP, and MDR3, 25 of which were novel. In our cohort, frequencies for risk alleles of BSEP (p.V444A) and MDR3 (p.I237I) polymorphisms were significantly overrepresented in patients without disease-causing mutation in the respective gene, indicating that these common variants can contribute to a cholestatic phenotype.

LAY SUMMARY

FIC1, BSEP, and MDR3 represent hepatobiliary transport proteins essential for bile formation. Genetic variants in these transporters underlie a broad spectrum of cholestatic liver diseases. To confirm a genetic contribution to the patients' phenotypes, gene sequencing of these three major cholestasis-related genes was performed in 427 patients and revealed 154 different variants of which 25 have not been previously reported in a database. In patients without a disease-causing mutation, common genetic variants were detected in a high number of cases, indicating that these common variants may contribute to cholestasis development.