Reference standard for serum bile acids in pregnancy

Verification of bile acid determination method and establishing reference intervals for biochemical and haematological parameters in third-trimester pregnant women

OBJECTIVES

The aims of this study were to verify the bile acids (BA) method and to establish reference intervals (RIs) for bile acids (BA) and biochemical and haematological parameters in Croatian pregnant women.

METHODS

BA spectrophotometric method verification was performed on Siemens Atellica Solution CH 930 automated analyser using Sentinel reagent. Stability, precision, trueness, linearity, and RIs, as well as lipemia interference were tested according to CLSI guidelines. BA, biochemical, and haematological parameters were measured in serum (BA, biochemical) and whole blood (haematological) samples of fasting healthy third-trimester pregnant women from Croatia (n=121). The establishment of the RIs was done a priori according to the CLSI EP28-A3C:2010 guideline. Selected reference individuals' data were analysed using parametric, non-parametric, and robust methods.

RESULTS

Stability study showed that BA are stable in serum samples for 2 days at 20 °C, 14 days at 4-8 °C, and 22 days at -20 °C. The precision study and adult RIs verification met the criteria. Linearity was verified for the concentration range of 3.5-172.1 μmol/L whereas the lipemia interference test showed a positive bias (%) in BA concentration. The determined reference limits generally exhibited better precision for haematological parameters, being lower than the upper recommended value 0.2, unlike biochemical parameters. Haematological parameters showed notable differences between pregnant and non-pregnant women, while many biochemical parameters' RIs remained similar. Only ALT and GGT showed lower non-comparable RI upper limits in the population pregnant women.

CONCLUSIONS

Spectrophotometric BA method showed satisfactory performance and all examined parameters were within the set criteria. Moreover, RIs for key biochemical and haematological parameters, including BAs, have been established for the first time in the population of Croatian pregnant women.

Serum bile acids associate with liver volume in polycystic liver disease and decrease upon treatment with lanreotide

BACKGROUND

Polycystic liver disease (PLD) is a common extrarenal manifestation of autosomal dominant polycystic kidney disease (ADPKD). Bile acids may play a role in PLD pathogenesis. We performed a post-hoc exploratory analysis of bile acids in ADPKD patients, who had participated in a trial on the effect of a somatostatin analogue. Our hypothesis was that serum bile acid levels increase in PLD, and that lanreotide, which reduces liver growth, may also reduce bile acid levels. Furthermore, in PLD, urinary excretion of bile acids might contribute to renal disease.

METHODS

With liquid chromatography-mass spectrometry, 11 bile acids in serum and 6 in urine were quantified in 105 PLD ADPKD patients and 52 age-, sex-, mutation- and eGFR-matched non-PLD ADPKD patients. Sampling was done at baseline and after 120 weeks of either lanreotide or standard care.

RESULTS

Baseline serum levels of taurine- and glycine-conjugated bile acids were higher in patients with larger livers. In PLD patients, multiple bile acids decreased upon treatment with lanreotide but remained stable in untreated subjects. Changes over time did not correlate with changes in liver volume. Urine bile acid levels did not change and did not correlate with renal disease progression.

CONCLUSION

In ADPKD patients with PLD, baseline serum bile acids were associated with liver volume. Lanreotide reduced bile acid levels and has previously been shown to reduce liver volume. However, in this study, the decrease in bile acids was not associated with the change in liver volume.

Role of aspartate aminotransferase to platelet ratio in the prediction and prognosis of intrahepatic cholestasis of pregnancy: A case-control study from a tertiary center

OBJECTIVE

To evaluate the aspartate aminotransferase to platelet ratio (APRI) score as a predictive and prognostic test in intrahepatic cholestasis of pregnancy (ICP).

METHODS

This study was conducted in 198 patients diagnosed with ICP and 204 healthy pregnant women who presented to a tertiary center between 2019 and 2022. APRI scores; laboratory findings in the first, second, and third trimesters; and perinatal outcomes were compared between the two groups. The ICP group was evaluated for correlation between APRI scores and composite adverse outcomes. Two different receiver operating characteristic analyses were performed to determine optimal cutoff values of predictive APRI score of ICP and composite adverse outcomes in patients with ICP.

RESULTS

Aspartate aminotransferase values and APRI scores were significantly higher in the ICP group in all trimesters (P < 0.001). The optimal cutoff values of APRI scores to predict ICP for the first, second, and third trimesters were 0.101 (79.7% sensitivity, 79.6% specificity), 0.103 (78.4% sensitivity, 76.3% specificity), and 0.098 (72.5% sensitivity, 72% specificity), respectively. APRI scores were statistically higher in patients with ICP with composite adverse outcomes in all trimesters (P values of 0.03, 0.04, and 0.01, respectively).

CONCLUSION

APRI score was found to be a valuable predictor of ICP and its adverse outcomes during the entire pregnancy.

[Intrahepatic cholestasis of pregnancy: French College of Obstetricians and Gynecologists guidelines for clinical practice]

OBJECTIVE

To identify strategies for reducing neonatal and maternal morbidity associated with intrahepatic cholestasis pregnancy (ICP).

MATERIAL AND METHODS

The quality of evidence of the literature was assessed following the GRADE methodology with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane, EMBASE and Google Scholar databases. The quality of the evidence was assessed (high, moderate, low, very low) and a (i) strong or (ii) weak recommendations or (iii) no recommendation were formulated. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations.

RESULTS

Of the 14 questions (from 12 PICO questions and one definition question outside the PICO format), there was agreement between the working group and the external reviewers on 14 (100%). The level of evidence of the literature was insufficient to provide a recommendation on two questions. ICP is defined by the occurrence of suggestive pruritus (palmoplantar, nocturnal) associated with a total bile acid level>10μmol/L or an alanine transaminase level above 2N after ruling out differential diagnoses. In the absence of suggestive symptoms of a differential diagnosis, it is recommended not to carry out additional biological or ultrasound tests. In women with CIP, ursodeoxycholic acid is recommended to reduce the intensity of maternal pruritus (Strong recommendation. Quality of the evidence moderate) and to decrease the level of total bile acids and alanine transaminases. (Strong recommendation. Quality of the evidence moderate). S-adenosyl-methionine, dexamethasone, guar gum or activated charcoal should not be used to reduce the intensity of maternal pruritus (Strong recommendation. Quality of evidence low), and there is insufficient data to recommend the use of antihistamines (No recommendation. Quality of evidence low). Rifampicin (Weak recommendation. Very low quality of evidence) or plasma exchange (Strong recommendation. Very low quality of evidence) should not be used to reduce maternal pruritus and perinatal morbidity. Serum monitoring of bile acids is recommended to reduce perinatal morbidity and mortality (stillbirth, prematurity) (Low recommendation. Quality of the evidence low). The level of evidence is insufficient to determine whether fetal heart rate or fetal ultrasound monitoring are useful to reduce perinatal morbidity (No recommendation). Birth is recommended when bile acid level is above 99μmol/L from 36 weeks gestation to reduce perinatal morbidity, in particular stillbirth. When bile acid level is above 99μmol/L is below 100μmol/L, women should be informed that induction of labor could be considered 37 and 39 weeks gestation to reduce perinatal morbidity. (Strong recommendation. Quality of evidence low). In postpartum, total bile acids and alanine transaminases level should be checked and normalized before prescribing estrogen-progestin contraception, ideally with a low estrogen dose (risk of recurrence of pruritus and cytolysis) (Low recommendation. Quality of evidence very low).

CONCLUSION

Although the quality of evidence regarding ICP gestational cholestasis remains low, there is a strong consensus in France, as shown by our Delphi study, on how to manage women with ICP. The reference first-line treatment is ursodeoxycholic acid.

Revisited role of the placenta in bile acid homeostasis

To date, the discussion concerning bile acids (BAs) during gestation is almost exclusively linked to pregnancy complications such as intrahepatic cholestasis of pregnancy (ICP) when maternal serum BA levels reach very high concentrations (>100 μM). Generally, the placenta is believed to serve as a protective barrier avoiding exposure of the growing fetus to excessive amounts of maternal BAs that might cause detrimental effects (e.g., intrauterine growth restriction and/or increased vulnerability to metabolic diseases). However, little is known about the precise role of the placenta in BA biosynthesis, transport, and metabolism in healthy pregnancies when serum BAs are at physiological levels (i.e., low maternal and high fetal BA concentrations). It is well known that primary BAs are synthesized from cholesterol in the liver and are later modified to secondary BA species by colonic bacteria. Besides the liver, BA synthesis in extrahepatic sites such as the brain elicits neuroprotective actions through inhibition of apoptosis as well as oxidative and endoplasmic reticulum stress. Even though historically BAs were thought to be only "detergent molecules" required for intestinal absorption of dietary fats, they are nowadays acknowledged as full signaling molecules. They modulate a myriad of signaling pathways with functional consequences on essential processes such as gluconeogenesis -one of the principal energy sources of the fetus- and cellular proliferation. The current manuscript discusses the potential multipotent roles of physiologically circulating BAs on developmental processes during gestation and provides a novel perspective in terms of the importance of the placenta as a previously unknown source of BAs. Since the principle "not too much, not too little" applicable to other signaling molecules may be also true for BAs, the risks associated with fetal exposure to excessive levels of BAs are discussed.

The Placenta-A New Source of Bile Acids during Healthy Pregnancy? First Results of a Gene Expression Study in Humans and Mice

Bile acids (BAs) are natural ligands for several receptors modulating cell activities. BAs are synthesized via the classic (neutral) and alternative (acidic) pathways. The classic pathway is initiated by CYP7A1/Cyp7a1, converting cholesterol to 7α-hydroxycholesterol, while the alternative pathway starts with hydroxylation of the cholesterol side chain, producing an oxysterol. In addition to originating from the liver, BAs are reported to be synthesized in the brain. We aimed at determining if the placenta potentially represents an extrahepatic source of BAs. Therefore, the mRNAs coding for selected enzymes involved in the hepatic BA synthesis machinery were screened in human term and CD1 mouse late gestation placentas from healthy pregnancies. Additionally, data from murine placenta and brain tissue were compared to determine whether the BA synthetic machinery is comparable in these organs. We found that CYP7A1, CYP46A1, and BAAT mRNAs are lacking in the human placenta, while corresponding homologs were detected in the murine placenta. Conversely, Cyp8b1 and Hsd17b1 mRNAs were undetected in the murine placenta, but these enzymes were found in the human placenta. CYP39A1/Cyp39a1 and cholesterol 25-hydroxylase (CH25H/Ch25h) mRNA expression were detected in the placentas of both species. When comparing murine placentas and brains, Cyp8b1 and Hsd17b1 mRNAs were only detected in the brain. We conclude that BA synthesis-related genes are placentally expressed in a species-specific manner. The potential placentally synthesized BAs could serve as endocrine and autocrine stimuli, which may play a role in fetoplacental growth and adaptation.

The Pathological Effects of Circulating Hydrophobic Bile Acids in Alzheimer's Disease

Recent clinical studies have revealed that the serum levels of toxic hydrophobic bile acids (deoxy cholic acid, lithocholic acid [LCA], and glycoursodeoxycholic acid) are significantly higher in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) when compared to control subjects. The elevated serum bile acids may be the result of hepatic peroxisomal dysfunction. Circulating hydrophobic bile acids are able to disrupt the blood-brain barrier and promote the formation of amyloid-β plaques through enhancing the oxidation of docosahexaenoic acid. Hydrophobic bile acid may find their ways into the neurons via the apical sodium-dependent bile acid transporter. It has been shown that hydrophobic bile acids impose their pathological effects by activating farnesoid X receptor and suppressing bile acid synthesis in the brain, blocking NMDA receptors, lowering brain oxysterol levels, and interfering with 17β-estradiol actions such as LCA by binding to E2 receptors (molecular modelling data exclusive to this paper). Hydrophobic bile acids may interfere with the sonic hedgehog signaling through alteration of cell membrane rafts and reducing brain 24(S)-hydroxycholesterol. This article will 1) analyze the pathological roles of circulating hydrophobic bile acids in the brain, 2) propose therapeutic approaches, and 3) conclude that consideration be given to reducing/monitoring toxic bile acid levels in patients with AD or aMCI, prior/in combination with other treatments.

Intrahepatic cholestasis of pregnancy: a comparison of Society for Maternal-Fetal Medicine and the Royal College of Obstetricians and Gynaecologists' guidelines

This study reviewed the literature regarding the diagnosis, antepartum surveillance, and timing of delivery of pregnancies complicated by intrahepatic cholestasis of pregnancy, comparing the guidelines published by the Society for Maternal-Fetal Medicine in February 2021 and those published by the Royal College of Obstetricians and Gynaecologists in the United Kingdom in June 2022. Several key differences exist in the clinical guidelines between the 2 organizations. With regard to the diagnosis of intrahepatic cholestasis of pregnancy, the Society for Maternal-Fetal Medicine considers any elevation in bile acids above the upper limit of normal in the setting of maternal pruritus diagnostic of intrahepatic cholestasis of pregnancy, whereas the Royal College of Obstetricians and Gynaecologists requires a pregnancy-specific elevated bile acid level of ≥19 mmol/L for diagnosis. Regarding the treatment of intrahepatic cholestasis of pregnancy, the Society for Maternal-Fetal Medicine recommends ursodeoxycholic acid as the first-line treatment of maternal symptoms. In contrast, the Royal College of Obstetricians and Gynaecologists specifically recommends against the routine use of ursodeoxycholic acid for intrahepatic cholestasis of pregnancy because of a lack of evidence regarding both maternal and fetal benefit. The Society for Maternal-Fetal Medicine recommends fetal surveillance at a gestational age when abnormal fetal testing would result in delivery being performed, whereas the Royal College of Obstetricians and Gynaecologists does not recommend any fetal testing beyond fetal kick count assessment. The Society for Maternal-Fetal Medicine recommends delivery at 36 to 39 weeks' gestation for intrahepatic cholestasis of pregnancy with bile acids <100 mmol/L and delivery at 36 weeks for bile acid levels >100 mmol/L. The Royal College of Obstetricians and Gynaecologists recommends serial assessment of bile acids with delivery timing stratified between 35- and 40-weeks' gestation according to bile acid levels.

Reference intervals for clinical biochemistry and haematology tests during normal pregnancy

BACKGROUND

Pregnancy induces physiological changes which affect biochemical and haematological parameters. As the significance of laboratory test results change throughout pregnancy, the reference interval (RI) or key result interpretive guide should be specific to pregnancy. This study sought to establish trimester-specific-RIs for routine biochemical and haematological tests in healthy white European women with singleton pregnancies with comparison to RIs for non-pregnant European adults.

METHODS

A retrospective analysis of a prospective longitudinal single-centre study of healthy pregnant women conducted between November 2018 and December 2020 in a tertiary academic hospital with approximately 3000 births annually. Inclusion criteria: signed informed consent, age ≥18 years, white European, body mass index (BMI) <25 kg/m2, blood pressure <140/90mmHg, non-smoker, no previous pathology or gestational diabetes. Trimester defined as T1: up to 13 weeks + 6 days, T2: 14-27 weeks + 6 days and T3: ≥28-41 weeks + 6 days. Baseline demographics, anthropometric and laboratory measurements were recorded. In total, 31 biochemical and 10 haematological ISO15189:2012 accredited tests were measured using Roche Cobas® and Sysmex XN-9100™ analysers, respectively. RIs were established according to the International Federation of Clinical Chemistry (IFCC) recommended method.

RESULTS

Apparently healthy pregnant women (n = 124) with bio-banked serum samples in each trimester were recruited. At the booking visit, 49.2% (n = 61) of participants were nulliparous, with median age of 34.4 (IQR: 31.3-37.3) years, gestational age of 89 (IQR: 84-93) days, BMI of 22.5 (IQR: 21.0-23.7) kg/m² and systolic and diastolic blood pressure of 116 (110-125) mmHg and 67 (61-75) mmHg, respectively.

CONCLUSIONS

Normative trimester-specific biological intervals for routinely requested biochemical and haematological medical laboratory tests were established. These RIs will be invaluable to result interpretation and the management of pregnant women.

Intrahepatic cholestasis of pregnancy - Time to redefine the reference range of total serum bile acids: A cross-sectional study

Objective

To establish pregnancy‐specific reference ranges for fasting and postprandial total serum bile acid (TSBA) concentrations.

Design

Cross‐sectional study.

Setting

Tertiary‐care university hospital.

Population

Healthy pregnant women at term admitted to the Obstetrics Department over a period of 1 year. Exclusion criteria were an established diagnosis of intrahepatic cholestasis of pregnancy (ICP) or any coexisting condition of increased risk for ICP.

Methods

Both fasting (after 8–14 h of fasting) and postprandial (2 h after meal) TSBA concentrations were measured in 612 women (with 528 fasting samples and 377 postprandial samples) by automated enzymatic spectrophotometric assay.

Main outcome measures

Fasting and postprandial TSBA concentrations in 612 women.

Results

Reference intervals of 4.4–14.1 μmol/L for fasting TSBA and 4.7–20.2 μmol/L for postprandial TSBA were established. The postprandial values were significantly higher than the fasting values, with a median increase of 1.0 μmol/L (p < 0.0001). A correlation between fasting TSBA concentrations and postprandial concentrations was found, as well as correlations with fetal sex, parity and assisted reproductive technologies. A seasonal pattern was noticed for both fasting and postprandial TSBA, with the highest values measured in the winter season (p < 0.01 and 0.02, respectively)

Conclusions

Normal pregnancy is associated with mild hypercholanaemia, and therefore a higher threshold should be considered for the diagnosis of ICP. We suggest using the upper reference limits observed in our healthy pregnant population (14 μmol/L for fasting TSBA and 20 μmol/L for postprandial TSBA). As the fasting measurement is more specific for the diagnosis, and the postprandial measurement is essential for the assessment of severity, it is recommended to measure both values rather than use random sampling.

Tweetable abstract

Normal pregnancy is associated with mild hypercholanaemia, a higher threshold should be considered for the diagnosis of ICP.

Normal pregnancy is associated with mild hypercholanaemia, a higher threshold should be considered for the diagnosis of ICP.

Linked article: This article is commented on by Ovadia et al., pp. 1897–1898. in this issue. To view this minicommentary visit https://doi.org/10.1111/1471‐0528.17171

Serum Bile Acid Levels in Women With Intrahepatic Cholestasis of Pregnancy in India

Introduction

Intrahepatic cholestasis of pregnancy (ICP) manifests as unexplained intense pruritus in the third trimester of pregnancy and is often diagnosed based on elevated serum bile acid measurement. There are no data from India on serum bile acid levels in pregnant women with ICP.

Methods

Pregnant women with significant pruritus during the third trimester of gestation and with elevated serum alanine aminotransferase and/or aspartate aminotransferase (normal: <40 IU/L) were taken as having ICP. Serum BA levels were measured in them and in nonpregnant women and healthy pregnant women without itching.

Results

Of the 3735 pregnant women screened, 105 (2.8%) had ICP (age 28 [26-32] years; gestational age 32 [30-36] weeks; primigravida 32.3%, and 95.3% normal fetal growth). Median (interquartile range) serum bile acid levels in nonpregnant women (n = 61; 28 [25-31] years) and pregnant women without ICP (n = 59; 28 [25-31] years) were similar (3.7 [1.6-5.1] μmol/L and 3.7 [2.2-5.8] μmol/L, respectively). By comparison, serum bile acid level in women with ICP (n = 105; 28 [26-32] years) was significantly higher (20.2 [12.7-39.5] μmol/L; P < 0.05 each), being above 10 μmol/L in 88 (83.8%). The optimum cut-off for the diagnosis of ICP in our population was ≥8.6 μmol/L, with sensitivity of 87.6%, specificity of 93.3% and area under the receiver-operator characteristics curve of 0.937 (95% CI: 0.904-0.970).

Conclusion

Serum BA levels in healthy Indian nonpregnant and pregnant women are similar to those in other populations and can be used to diagnose ICP with an optimal cut-off being 8.6 μmol/L.

Obstetric Cholestasis: Investigation of a suspected high incidence in the West of Ireland

AIM

To identify the incidence of Obstetric Cholestasis in a Maternity unit. To compare our investigation, criteria for diagnosis and management plan with National Guidelines. To assess adverse maternal and neonatal outcomes associated with this condition.

METHOD

Serum Bile Acid requests are sent to an external laboratory, Biomnis in Dublin, for processing. A log of 2018 requests was obtained from Biochemistry. The pregnant patients with values > 8 mmol/L were selected. A data collection proforma was designed and retrospective chart review performed.

RESULTS

Of the 1302 births in SUH in 2018, 42 women met the criteria resulting in a suspected incidence of 3.2% (n = 42). 9.5%(n = 4) of patients had a history of OC in a previous pregnancy. Bile acid values ranged from 8.1 to 124 mmol/L. LFTs were deranged in 81% (n = 34) of patients. Gestation at delivery ranged from 35 weeks to 40 + 9. OC alone was the indication for induction in 57%9n = 24). CS in 43% (n = 20) and Vaginal birth in 57% (n = 25). Neonatal outcome: 7% (n = 3) reduced APGAR, 7% (n = 3) passed meconium, 9% (n = 4) NICU admission, no stillbirths.

CONCLUSION

Suspected incidence of 3.2% (n = 42) is significantly higher than the stated 0.7% across multi-ethnic populations. Greater congruence is required on the BA cut off value for diagnosis as there is no specified value in guidelines. While we may be over diagnosing patients based on BA level, we are also undertreating them, with 55% (n = 23) receiving Ursofalc. There was no neonatal mortality.

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.

Maternal serum calprotectin level in intrahepatic cholestasis of pregnancy

AIM

This study aimed to investigate maternal serum levels of calprotectin in patients with intrahepatic cholestasis of pregnancy (ICP) and to compare these with serum calprotectin levels in healthy pregnant women.

METHODS

Ninety pregnant women (ICP group, n = 45; healthy control group, n = 45) were included in the study. The gestational age and body mass index of the participants in the two groups were similar. This prospective cross-sectional study was conducted between November 2019 and May 2020 in the perinatology department of University of Health Sciences Doctor Zekai Tahir Burak Women's Education Hospital, Ankara, Turkey. Patients were recruited from those attending the perinatology outpatient and inpatient clinics. Biochemical (alanine aminotransferase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), total bilirubin), fasting bile acid, hemogram, and calprotectin parameters of maternal blood were evaluated.

RESULTS

The mean fasting bile acid value in the ICP group was 30.3 ± 27.3 μmol, with severe ICP present in 11 (24.4%) patients. ALT, AST, LDH, total bilirubin, and mean platelet volume (MPV) values in the ICP group were higher and the red cell distribution width (RDW) value was lower than those in the control group (p < 0.001). The mean serum calprotectin levels in the control group and ICP group were 48.0 ± 10.4 and 765.4 ± 126.8 μg, respectively (p < 0.001). There was no significant correlation between serum fasting bile acid levels and serum calprotectin levels in the ICP group (p > 0.005).

CONCLUSION

Serum levels of calprotectin in patients with ICP were higher than those in healthy pregnant women. The serum calprotectin level may be an important diagnostic marker of ICP.

Prenatal ethanol exposure increases maternal bile acids through placental transport pathway

High maternal serum bile acid level is common and sometimes harmful to the gravida. This study aimed to confirm the bile acid phenotypic change caused by prenatal ethanol exposure (PEE) and elucidate its placental mechanism. Pregnant Wistar rats were administered intragastrically with ethanol 4 g/kg⋅d from gestational day 9-20. Total bile acids (TBA) were detected in maternal, fetal serum and placental tissues, increasing significantly in the serum but no significant change in the placental tissues. Meta-analysis was performed and verified the efficacy of the PEE-induced model based on published data from several relevant studies. Mining of microarray data from human and rat placental sources identified the involvement of bile acid metabolism and its significant genes, which were verified by RT-qPCR and western blotting on tissues and treated BeWo cells with the administration of FXR/PXR siRNAs or FXR/PXR agonists. Our examination, consistent with microarray data and wet experiments, showed that organic anion transporter polypeptide-related protein 2B1 (Oatp2b1), multidrug resistance-associated proteins 3 (Mrp3) and breast cancer resistance protein (Bcrp) expression were increased, while nuclear receptor farnesoid X receptor (Fxr) was decreased but pregnane X receptor (Pxr) was increased. Furthermore, the interventional experiments confirmed that FXR regulated Bcrp while PXR regulated Oatp2b1 and Mrp3. In summary, PEE could induce high bile acid level in maternal serum and its mechanism is associated with the high expression of BCRP/MRP3/OATP2B1 in the placenta through up-regulating PXR and down-regulating FXR, thereby leading to an excessive bile acid transport to maternal blood via the placenta. Our study provides a novel perspective in terms of placenta, explaining the increased maternal blood bile acids under the toxicity of PEE.

[Intrahepatic cholestasis of pregnancy]

Die Schwangerschaftscholestase („intrahepatic cholestasis of pregnancy“, ICP) ist die häufigste schwangerschaftsspezifische Lebererkrankung. Das Leitsymptom Juckreiz sowie eine begleitende Serumkonzentrationserhöhung von Gallensäuren und/oder der Alaninaminotransferase (ALT) sind wegweisend in der Diagnosestellung. Die mütterliche Prognose ist gut. Das fetale Outcome ist abhängig von der Gallensäurenkonzentration. Die ICP ist dabei sowohl mit Frühgeburt als auch mit intrauterinem Fruchttod (IUFT) assoziiert. Dieser ist Folge einer akuten fetalen Asphyxie, nicht einer chronischen uteroplazentaren Dysfunktion. Ein prädiktives Monitoring, z. B. durch Kardiotokographie (CTG) oder Ultraschall gibt es nicht. Eine medikamentöse Therapie mit Ursodeoxycholsäure (UDCA) bessert den Juckreiz, aber beeinflusst das fetale Outcome nicht nachweislich. Eine Entbindungsindikation ist in Abhängigkeit von Gallensäurenkonzentration und Gestationsalter gegeben. In Folgeschwangerschaften besteht ein hohes Wiederholungsrisiko.

Re-evaluating diagnostic thresholds for intrahepatic cholestasis of pregnancy: case-control and cohort study

OBJECTIVE

To determine the optimal total serum bile acid (TSBA) threshold and sampling time for accurate intrahepatic cholestasis of pregnancy (ICP) diagnosis.

DESIGN

Case-control, retrospective cohort studies.

SETTING

Antenatal clinics, clinical research facilities.

POPULATION

Women with ICP or uncomplicated pregnancies.

METHODS

Serial TSBA measurements were performed pre-/postprandially in 42 women with ICP or uncomplicated pregnancy. Third-trimester non-fasting TSBA reference ranges were calculated from 561 women of black, south Asian and white ethnicity. Rates of adverse perinatal outcomes for women with ICP but peak non-fasting TSBA below the upper reference range limit were compared with those in healthy populations.

MAIN OUTCOME MEASURES

Sensitivity and specificity of common TSBA thresholds for ICP diagnosis, using fasting and postprandial TSBA. Calculation of normal reference ranges of non-fasting TSBA.

RESULTS

Concentrations of TSBA increased markedly postprandially in all groups, with overlap between healthy pregnancy and mild ICP (TSBA <40 μmol/l). The specificity of ICP diagnosis was higher when fasting, but corresponded to <30% sensitivity for diagnosis of mild disease. Using TSBA ≥40 μmol/l to define severe ICP, fasting measurements identified 9% (1/11), whereas non-fasting measurements detected over 91% with severe ICP. The highest upper limit of the non-fasting TSBA reference range was 18.3 µmol/l (95% confidence interval: 15.0-35.6 μmol/l). A re-evaluation of published ICP meta-analysis data demonstrated no increase in spontaneous preterm birth or stillbirth in women with TSBA <19 µmol/l.

CONCLUSIONS

Postprandial TSBA levels are required to identify high-risk ICP pregnancies (TSBA ≥40 μmol/l). The postprandial rise in TSBA in normal pregnancy indicates that a non-fasting threshold of ≥19 µmol/l would improve diagnostic accuracy.

TWEETABLE ABSTRACT

Non-fasting bile acids improve the diagnostic accuracy of intrahepatic cholestasis of pregnancy diagnosis.

Cholestasis: A Prospective Study of Perinatal Outcomes and Time to Symptom Improvement

OBJECTIVE

Although intrahepatic cholestasis of pregnancy (ICP) remains poorly understood, there are several perinatal complications associated with this condition. This study aimed to examine perinatal outcomes of women with ICP, evaluate outcomes according to severity of disease, and monitor time to symptom improvement following diagnosis.

STUDY DESIGN

It involves a prospective, observational study of women with ICP at a single institution. Women with new-onset pruritus without rash were referred to a high-risk obstetrics clinic and evaluated with fasting total bile acids (TBA). Laboratory-confirmed ICP was defined as fasting TBA ≥10 µmol/L. Following diagnosis, a standardized protocol was utilized, including treatment with ursodeoxycholic acid (UDCA). Perinatal outcomes were compared amongst those with and without ICP, and to the general population. Women with ICP were further analyzed based on maximum TBA: 10 to 39, 40 to 99, and ≥100 µmol/L. A Kaplan-Meier survival curve was used to analyze time to symptom improvement.

RESULTS

A total of 404 patients were evaluated and 212 (52%) were diagnosed with ICP. The mean gestational age at diagnosis was 34.1 ± 3.3 weeks. When comparing those with ICP to those not confirmed, and to the general population, there were no differences in age, parity, mode of delivery, preeclampsia, or stillbirth (p > 0.05). Preterm birth was significantly associated with ICP (p < 0.01). This relationship was significant across increasing severity of TBA (p < 0.01) and persisted when examining rates of spontaneous preterm birth (p < 0.01). All women with fasting TBA ≥40 µmol/L delivered preterm due to premature rupture of membranes or spontaneous labor. Time to symptom improvement after diagnosis was over 2 weeks on average; however, this time increased with worsening severity of disease.

CONCLUSION

Despite treatment with UDCA, women with ICP are at increased risk for spontaneous preterm birth, and this risk significantly increased with severity of disease. Although not significant, a trend exists between increasing time to symptom improvement and worsening severity of disease.

KEY POINTS

· Preterm birth is significantly increased in patients diagnosed with intrahepatic cholestasis of pregnancy.. · The risk of preterm birth in women with ICP increases across increasing strata of disease.. · Following initiation of treatment in patients with ICP, symptom improvement takes more than 2 weeks..

Structural modifications that increase gut restriction of bile acid derivatives

Bile acid derivatives have been investigated as possible therapeutics for a wide array of conditions, including several for which gut-restricted analogs would likely be preferred. These include the prevention of Clostridioides difficile infection (CDI) and the treatment of inflammatory bowel disease (IBD). The design of gut-restricted bile acid analogs, however, is complicated by the highly efficient enterohepatic circulation system that typically reabsorbs these compounds from the digestive tract for subsequent return to the liver. Herein, we report that incorporation of a sulfate group at the 7-position of the bile acid scaffold reduces oral bioavailability and increases fecal recovery in two pairs of compounds designed to inhibit the germination of C. difficile spores. A different approach was necessary for designing gut-restricted bile acid-based TGR5 agonists for the treatment of IBD, as the incorporation of a 7-sulfate group reduces activity at this receptor. Instead, building on our previous discovery that incorporation of a 7-methoxy group into chenodeoxycholic acid derivatives greatly increases their TGR5 receptor potency, we determined that an N-methyl-d-glucamine group could be conjugated to the scaffold to obtain a compound with an excellent mix of potency at the TGR5 receptor, low oral exposure, and good fecal recovery.

Society for Maternal-Fetal Medicine Consult Series #53: Intrahepatic cholestasis of pregnancy: Replaces Consult #13, April 2011

Intrahepatic cholestasis of pregnancy is a hepatic disorder characterized by pruritus and an elevation in serum bile acid levels. Although intrahepatic cholestasis of pregnancy poses little risk for women, this condition carries a significant risk for the fetus, including complications such as preterm delivery, meconium-stained amniotic fluid, and stillbirth. The purpose of this Consult is to review the current literature on intrahepatic cholestasis of pregnancy and provide recommendations based on the available evidence. The recommendations by the Society for Maternal-Fetal Medicine are as follows: (1) we recommend measurement of serum bile acid and liver transaminase levels in patients with suspected intrahepatic cholestasis of pregnancy (GRADE 1B); (2) we recommend that ursodeoxycholic acid be used as the first-line agent for the treatment of maternal symptoms of intrahepatic cholestasis of pregnancy (GRADE 1A); (3) we suggest that patients with a diagnosis of intrahepatic cholestasis of pregnancy begin antenatal fetal surveillance at a gestational age when delivery would be performed in response to abnormal fetal testing results or at the time of diagnosis if the diagnosis is made later in gestation (GRADE 2C); (4) we recommend that patients with total bile acid levels of ≥100 μmol/L be offered delivery at 36 0/7 weeks of gestation, given that the risk of stillbirth increases substantially around this gestational age (GRADE 1B); (5) we recommend delivery between 36 0/7 and 39 0/7 weeks of gestation for patients with intrahepatic cholestasis of pregnancy and total bile acid levels of <100 μmol/L (GRADE 1C); (6) we recommend administration of antenatal corticosteroids for fetal lung maturity for patients delivering before 37 0/7 weeks of gestation if not previously administered (GRADE 1A); (7) we recommend against preterm delivery at <37 weeks of gestation in patients with a clinical diagnosis of intrahepatic cholestasis of pregnancy without laboratory confirmation of elevated bile acid levels (GRADE 1B).

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.

Serum Bile Acids in Patients With Primary Open-angle Glaucoma

PURPOSE

To measure the serum bile acids (SBA) in patients with primary open-angle glaucoma (POAG) and to compare with nonglaucomatous controls.

PATIENTS AND METHODS

A hospital-based case control study of 90 patients above the age of 40 years was conducted. Patients with POAG formed the study group and individuals without glaucoma in the same age group formed the control group. SBA estimation was done using ELISA kit enzymatic assay technique and the median value was compared between the 2 groups.

RESULTS

The median of SBA level was found to be more in POAG patients when compared with the control group. The difference was statistically significant (P<0.001). Median SBA level was not affected by the age or sex of the participants in the study.

CONCLUSIONS

"Bile acids" may have a role in the oxidative stress and apoptosis involved in the pathophysiology of POAG.

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.

Analytical evaluation of three enzymatic assays for measuring total bile acids in plasma using a fully-automated clinical chemistry platform

BACKGROUND

Although the clinical significance of measuring bile acids concentration in plasma or serum has been recognized for long in patients with hepatobiliary disease and/or bile acid malabsorption, the reference separation techniques are expensive and mostly unsuitable for early diagnosis and for measuring large volumes of samples. Therefore, this study was aimed to evaluate the analytical performance of three commercial enzymatic techniques for measuring total bile acids in plasma using a fully-automated clinical chemistry platform.

METHODS

Three commercial enzymatic assays (from Diazyme, Randox and Sentinel) were adapted for use on a Cobas Roche c501. We performed imprecision and linearity studies, and we compared results with those obtained using a reference liquid chromatography-mass spectrometry (LC-MS) technique on an identical set of lithium-heparin plasma samples.

RESULTS

Total imprecision was optimal, always equal or lower than 3%. All assays had optimal linearity between 3-138 μmol/L. The comparison studies showed good correlation with LC-MS data (Spearman's correlation coefficients always >0.92), but all plasma samples values were significantly underestimated using the commercial enzymatic assays (-44% for Diazyme, -16% for Randox and -12% for Sentinel). The agreement at the 10 and 40 μmol/L diagnostic thresholds of total bile acids in plasma ranged between 86-92%. This discrepancy was found to be mainly attributable to a heterogeneous composition in terms of bile acids content of the three assay calibrators.

CONCLUSIONS

This study suggests that the analytical performance of the three commercial enzymatic assays is excellent, thus confirming that automation of this important test by means of enzymatic assessment may be feasible, practical, reliable and supposedly cheap. Nevertheless, the underestimation of values compared to the reference LC-MS also suggests that the local definition and validation of reference ranges according to the combination between the specific enzymatic assay and the different clinical chemistry platforms may be advisable.

Bile Acid Determination after Standardized Glucose Load in Pregnant Women

Objective Intrahepatic cholestasis of pregnancy (ICP) is a rare liver disorder, usually manifesting in the third trimester and associated with increased perinatal morbidity and mortality. The hallmark laboratory abnormality in ICP is elevated fasting serum bile acids; however, there are limited data on whether a nonfasting state affects a pregnant woman's total bile acids. This study assesses fasting and nonfasting bile acid levels in 10 healthy pregnant women after a standardized glucose load to provide insight into the effects of a glucose load on bile acid profiles. Study Design Pilot prospective cohort analysis of serum bile acids in pregnant women. A total of 10 healthy pregnant women from 28 to 32 weeks' gestation were recruited for the study before undergoing a glucose tolerance test. Total serum bile acids were collected for each subject in the overnight fasting state, and 1 and 3 hours after the 100-g glucose load. Results There was a statistically significant difference between fasting versus 3-hour values. There was no statistically significant difference between fasting versus 1-hour and 1-hour versus 3-hour values. Conclusion There is a difference between fasting and nonfasting total serum bile acids after a 100-g glucose load in healthy pregnant women.

Intrahepatic Cholestasis of Pregnancy and Serum Bile Acids in HIV-Infected Pregnant Women

OBJECTIVES

Intra-hepatic cholestasis of pregnancy (ICP) is uncommon, but has severe effects on pregnancy outcomes. ICP is characterized by elevated serum bile acids and liver enzymes and preferentially affects women with liver disorders. We compared bile acids and pregnancy outcomes of HIV-infected pregnant women, who commonly have elevated live enzymes, with uninfected controls.

METHODS

Twenty-four HIV-infected, including 2 co-infected with hepatitis C virus (HCV), and 25 uninfected women were tested during early and late pregnancy and postpartum.

RESULTS

After exclusion of the HCV-infected women, serum bile acids were similar in HIV-infected and uninfected participants. -glutamyl transpeptidase was elevated in HIV-infected compared with uninfected women during pregnancy and postpartum. Bilirubin and aspartate transaminase were higher in uninfected compared with HIV-infected women in early pregnancy, but subsequently similar. Bile acids in late pregnancy correlated with bile acids in the baby at birth. An HIV- and HCV-co-infected pregnant woman with active hepatitis developed ICP complicated by fetal distress. Another co-infected participant without active hepatitis had an uneventful pregnancy and delivery.

CONCLUSION

In the absence of HCV co-infection, bile acid metabolism appeared to be similar in HIV-infected and uninfected pregnant women. Both HIV-infected and uninfected pregnant women had mild liver enzyme elevations.

Bile acids in a multicenter, population-based case-control study of stillbirth

OBJECTIVE

We sought to compare bile acids in women with and without stillbirth in a population-based study.

STUDY DESIGN

The Stillbirth Collaborative Research Network conducted a multisite, population-based case-control study of stillbirth (fetal deaths ≥20 weeks). Maternal sera were obtained at the time of enrollment and frozen at -80°C until assay for bile acids.

RESULTS

Assays were performed in 581 women with stillbirth and 1546 women with live births. Bile acid levels were slightly higher in women with stillbirth (geometric mean [95% confidence interval {CI}] = 3.2 [3.0-3.5]) compared to live births (2.9 [2.7-3.1], P = .0327). However, the difference was not significant after adjustment for baseline risk factors for stillbirth. The proportion of women with elevated levels (≥10 or ≥40 μmol/L) was similar in stillbirths and live births. Results were similar when the analysis was limited to subsets of stillbirths and live births. In women with stillbirths not associated with fetal anomalies or obstetric complications bile acid levels were higher than in women with term live births (geometric mean [95% CI] = 3.4 [3.0-3.8] vs 2.9 [2.7-3.0], P = .0152, unadjusted; P = .06, adjusted). However, a similar proportion of women in both groups had levels ≥10 μmol/L (10.7 vs 7.2%; odds ratio [OR], 1.54; 95% CI, 0.97-2.44; adjusted OR, 1.29; 95% CI, 0.78-2.15) and ≥40 μmol/L (1.7 vs 0.7%; OR, 2.58; 95% CI, 0.85-7.84; adjusted OR, 2.28; 95% CI, 0.79-6.56).

CONCLUSION

Our data do not support testing for bile acids in cases of stillbirth in the absence of clinical evidence of intrahepatic cholestasis of pregnancy.

Gastrointestinal and liver disease in pregnancy

This chapter on the gastrointestinal and hepatic systems in pregnancy focusses on those conditions that are frequent and troublesome (gastro-oesophageal reflux and constipation), distressing (hyperemesis gravidarum) or potentially fatal (obstetric cholestasis, acute fatty liver of pregnancy and HELLP (haemolysis, elevated liver enzymes, low platelets) syndrome). It also highlights the clinical challenge obstetricians may face in managing rare conditions such as the Budd-Chiari syndrome, liver transplantation, primary biliary cirrhosis and Wilson disease. The clinical presentation of liver and gastrointestinal dysfunction in pregnancy is not specific, and certain 'abnormalities' may represent physiological changes of pregnancy. Diagnosis and management are often difficult because of atypical symptoms, a reluctance to use invasive investigations and concerns about the teratogenicity of the medications. The best available evidence to manage these conditions is discussed in the chapter.

Interpretation and management of hepatic abnormalities in pregnancy

The spectrum of liver disease in pregnancy includes liver disease unrelated to pregnancy, liver diseases that occur with increased frequency or severity in pregnancy, and liver disease specific to pregnancy. Diseases of the liver unique to pregnancy reliably occur at specific points in the gestational spectrum. Thus, gestational age, a comprehensive history, and a clinically driven diagnostic evaluation is critical in approaching a pregnant patient with abnormal liver chemistries or function. Early recognition of these conditions is important and although management may be expectant, some patients require targeted therapy or necessitate prompt delivery, which can be life-saving to both mother and child.

Reproductive endocrinology: maternal cholestasis and offspring metabolic abnormalities

Papacleovoulou and colleagues demonstrate that maternal cholestasis during pregnancy is associated with offspring adiposity and metabolic abnormalities, both in humans and in mice. This study reinforces the overwhelming evidence of the critical role of the in utero environment as a major determinant of adult health and disease.

Hepatic bile acids and bile acid-related gene expression in pregnant and lactating rats

Background. Significant physiological changes occur during pregnancy and lactation. Intrahepatic cholestasis of pregnancy (ICP) is a liver disease closely related to disruption of bile acid homeostasis. The objective of this study was to examine the regulation of bile acid synthesis and transport in normal pregnant and lactating rats. Materials and Methods. Livers from timed pregnant SD rats were collected on gestational days (GD) 10, 14 and 19, and postnatal days (PND) 1, 7, 14 and 21. Total bile acids were determined by the enzymatic method, total RNA was isolated and subjected to real time RT-PCR analysis. Liver protein was extracted for western-blot analysis. Results. Under physiological conditions hepatic bile acids were not elevated during pregnancy but increased during lactation in rats. Bile acid synthesis rate-limiting enzyme Cyp7a1 was unchanged on gestational days, but increased on PND14 and 21 at mRNA and protein levels. Expression of Cyp8b1, Cyp27a1 and Cyp7b1 was also higher during lactation. The mRNA levels of small heterodimer partner (SHP) and protein levels of farnesoid X receptor (FXR) were increased during pregnancy and lactation. Bile acid transporters Ntcp, Bsep, Mrp3 and Mrp4 were lower at gestation, but increased during lactation. Hepatic Oatp transporters were decreased during pregnancy and lactation. Conclusion. Hepatic bile acid homeostasis is maintained during normal pregnancy in rats, probably through the FXR-SHP regulation. The expression of bile acid synthesis genes and liver bile acid accumulation were increased during lactation, together with increased expression of bile acid efflux transporter Bsep, Mrp3 and Mrp4.