Recognition of asymptomatic hypercholanemia of pregnancy: Different clinical features, fetal outcomes and bile acids metabolism from intrahepatic cholestasis of pregnancy

The correlation between serum total bile acid and adverse perinatal outcomes in pregnant women with intrahepatic cholestasis of pregnancy (ICP) and non-ICP hypercholanemia of pregnancy

BACKGROUND

The association between excessive serum total bile acid (TBA) and adverse perinatal outcomes in individuals with non-intrahepatic cholestasis of pregnancy (non-ICP) hypercholanemia has not been determined, and it is unclear if this link is similar to that observed in patients with ICP.

OBJECTIVE

To examine the adverse perinatal outcomes in two specific subcategories: those with ICP and those with non-ICP, including individuals with liver disease and asymptomatic hypercholanemia of pregnancy (AHP), at different levels of TBA. Investigate the correlation between TBA levels and adverse perinatal outcomes of ICP, liver disease, and AHP.

METHODS

From 2013 to 2021, pregnant women with excessive TBA levels were taken from the electronic medical record database of our hospital and categorized into three groups: ICP (n = 160), liver disease (n = 164), and AHP (n = 650). This was done as part of a retrospective cohort research project. Multivariable regression and subgroup analyses were performed to examine the association between TBA levels and adverse perinatal outcomes in each group.

RESULTS

The study found no significant differences in adverse perinatal outcomes between the ICP and liver disease groups at different TBA levels. However, at moderate TBA levels, both groups had a higher risk of adverse perinatal outcomes than the AHP group (p < 0.017). Among liver disease cases with TBA ≥ 100µmol/L, three cases of perinatal deaths (6.67%) associated with moderate-to-severe acute hepatitis occurred between 27 and 33 weeks of gestation. A 59% higher chance of perinatal death was found for every 10 µmol/L rise in TBA, even after significant variables and confounders were taken into account (adjusted odds ratio (aOR) = 1.59; 95% confidence interval (CI): 1.06-2.40; p = 0.03).

CONCLUSIONS

If a pregnant woman has moderate-to-severe liver disease and TBA ≥ 100µmol/L, preterm termination of pregnancy (before 34 weeks) may be considered.

Quantitative comparison of bile acid glucuronides sub-metabolome between intrahepatic cholestasis and healthy pregnant women

Because of the pathological indication and the physiological functions, bile acids (BAs) have occupied the research hotspot in recent decades. Although extensive efforts have been paid onto BAs sub-metabolome characterization, as the subfamily, BA glucuronides (gluA-BAs) profile is seldom concerned. Here, we made efforts to develop a LC-MS/MS program enabling quantitative gluA-BAs sub-metabolome characterization and to explore the differential species in serum between intrahepatic cholestasis of pregnancy (ICP) patients and healthy subjects. To gain as many authentic gluA-BAs as possible, liver microsomes from humans, rats, and mice were deployed to conjugate glucuronyl group to authentic BAs through in vitro incubation. Eighty gluA-BAs were captured and subsequently served as authentic compounds to correlate MS/MS spectral behaviors to structural features using squared energy-resolved MS program. Optimal collision energy (OCE) of [M-H]->[M-H-176.1]- was jointly administrated by [M-H]- mass and glucuronidation site, and identical exciting energies corresponding to 50% survival rate of 1st-generation fragment ion (EE50) were observed merely when the aglycone of a gluA-BA was consistent with the suspected structure. Through integrating high-resolution m/z, OCE, and EE50 information to identify gluA-BAs in a BAs pool, 97 ones were found and identified, and further, quantitative program was built for all annotated gluA-BAs by assigning OCEs to [M-H]->[M-H-176.1]- ion transitions. Quantitative gluA-BAs sub-metabolome of ICP was different from that of the healthy group. More GCDCA-3-G, GDCA-3-G, TCDCA-7-G, TDCA-3-G, and T-β-MCA-3-G were distributed in the ICP group. Above all, this study not only offered a promising analytical tool for in-depth gluA-BAs sub-metabolome characterization, but also clarified gluA-BAs allowing the differentiation of ICP and healthy subjects.

An omics review and perspective of researches on intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is one of the common pregnancy complications that may threaten the health of both pregnant women and their fetuses. Hence, it is of vital importance to identify key moleculars and the associated functional pathways of ICP, which will help us to better understand the pathological mechanisms as well as to develop precise clinical biomarkers. The emerging and developing of multiple omics approaches enable comprehensive studies of the genome, transcriptome, proteome and metabolome of clinical samples. The present review collected and summarized the omics based studies of ICP, aiming to provide an overview of the current progress, limitations and future directions. Briefly, these studies covered a broad range of research contents by the comparing of different experimental groups including ICP patients, ICP subtypes, ICP fetuses, ICP models and other complications. Correspondingly, the studied samples contain various types of clinical samples, in vitro cultured tissues, cell lines and the samples from animal models. According to the main research objectives, we further categorized these studies into two groups: pathogenesis and diagnosis analyses. The pathogenesis studies identified tens of functional pathways that may represent the key regulatory events for the occurrence, progression, treatment and fetal effects of ICP. On the other hand, the diagnosis studies tested more than 40 potential models for the early-prediction, diagnosis, grading, prognosis or differential diagnosis of ICP. Apart from these achievements, we also evaluated the limitations of current studies, and emphasized that many aspects of clinical characteristics, sample processing, and analytical method can greatly affect the reliability and repeatability of omics results. Finally, we also pointed out several new directions for the omics based analyses of ICP and other perinatal associated conditions in the future.

Pregnancy outcomes following antenatal screening for intrahepatic cholestasis of pregnancy (ICP)

OBJECTIVE

To evaluate the maternal and perinatal outcomes following antenatal screening for ICP using a retrospective approach.

MATERIALS AND METHODS

A retrospective study was conducted at the second affiliated hospital of Chongqing Medical University, Chongqing, China, from 2012 to 2017. Pregnant women registered for antenatal in our hospital were screened for ICP. The pregnant women with detailed delivery record and presenting with the diagnosis of ICP based on TBA level ≥10 mmol/L and abnormal liver enzymes were included in the study.

METHOD

The pregnant women with detailed delivery records presenting with the diagnosis of ICP based on TBA level ≥10 mmol/L and abnormal liver enzymes were included in the study. 1410 pregnant women were enrolled in this study. We selected 940 pregnant women without the diagnosis of ICP as our control and 470 pregnant women diagnosed with ICP as our case study. Data collection and sampling in the control group was done using microsoft excel (version 16.61) random number generator.

RESULTS

The mean age of the pregnant women and the gestational age at the time of diagnosis of ICP were 29.01 ± 4.3 years and 31.90 ± 8.83 weeks, respectively. It was found that a significant number of patients with ICP had a preterm birth and low birth weight (LBW), n = 151 (32.5%) P < 0.001 and n = 70 (14.9%) P < 0.001, respectively. A significant number of patients in the case group had a history of liver disease and gall bladder disease, p < 0.001 and p = 0.005, respectively, and a higher rate of GDM p < 0.001. Despite treatment, high TBA titer among ICP patients was associated with preterm delivery.

CONCLUSION

ICP in pregnancy leads to complications and poor perinatal outcomes. Fetal outcomes depend on the TBA levels; therefore, early diagnosis of ICP through routine screening followed by treatment is recommended in high-risk persons/areas.

CYP2D6 Activity Is Correlated with Changes in Plasma Concentrations of Taurocholic Acid during Pregnancy and Postpartum in CYP2D6 Extensive Metabolizers

Cytochrome P450 2D6 (CYP2D6) is involved in the metabolism of >20% of marketed drugs. CYP2D6 expression and activity exhibit high interindividual variability and is induced during pregnancy. The farnesoid X receptor (FXR) is a transcriptional regulator of CYP2D6 that is activated by bile acids. In pregnancy, elevated plasma bile acid concentrations are associated with maternal and fetal risks. However, modest changes in bile acid concentrations may occur during healthy pregnancy, thereby altering FXR signaling. A previous study demonstrated that hepatic tissue concentrations of bile acids positively correlated with the hepatic mRNA expression of CYP2D6. This study sought to characterize the plasma bile acid metabolome in healthy women (n = 47) during midpregnancy (25-28 weeks gestation) and ≥3 months postpartum and to determine if plasma bile acids correlate with CYP2D6 activity. It is hypothesized that during pregnancy, plasma bile acids would favor less hydrophobic bile acids (cholic acid vs. chenodeoxycholic acid) and that plasma concentrations of cholic acid and its conjugates would positively correlate with the urinary ratio of dextrorphan/dextromethorphan. At 25-28 weeks gestation, taurine-conjugated bile acids comprised 23% of the quantified serum bile acids compared with 7% ≥3 months postpartum. Taurocholic acid positively associated with the urinary ratio of dextrorphan/dextromethorphan, a biomarker of CYP2D6 activity. Collectively, these results confirm that the bile acid plasma metabolome differs between pregnancy and postpartum and provide evidence that taurocholic acid may impact CYP2D6 activity during pregnancy. SIGNIFICANCE STATEMENT: Bile acid homeostasis is altered in pregnancy, and plasma concentrations of taurocholic acid positively correlate with CYP2D6 activity. Differences between plasma and/or tissue concentrations of farnesoid X receptor ligands such as bile acids may contribute to the high interindividual variability in CYP2D6 expression and activity.

Bile Acids in Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is the most common, reversible, and closely related to pregnancy condition characterized by elevated levels of bile acids (BAs) in blood serum and an increased risk of adverse perinatal outcomes. Due to the complex interactions between the mother and the fetus in metabolism and transplacental BAs transport, ICP is classified as a fetal-maternal disease. The disease is usually mild in pregnant women, but it can be fatal to the fetus, leading to numerous complications, including intrauterine death. The pathophysiology of the disease is based on inflammatory mechanisms caused by elevated BA levels. Although ICP cannot be completely prevented, its early diagnosis and prompt management significantly reduce the risk of fetal complications, the most serious of which is unexpected intrauterine death. It is worth emphasizing that all diagnostics and management of ICP during pregnancy are based on BA levels. Therefore, it is important to standardize the criteria for diagnosis, as well as recommendations for management depending on the level of BAs, which undoubtedly determines the impact on the fetus. The purpose of this review is to present the potential and importance of BAs in the detection and rules of medical procedure in ICP.

Application of metabolomics in intrahepatic cholestasis of pregnancy: a systematic review

Background

Intrahepatic cholestasis of pregnancy (ICP) is a severe idiopathic disorder of bile metabolism; however, the etiology and pathogenesis of ICP remain unclear.

Aims

This study comprehensively reviewed metabolomics studies related to ICP, to help in identifying the pathophysiological changes of ICP and evaluating the potential application of metabolomics in its diagnosis.

Methods

Relevant articles were searched through 2 online databases (PubMed and Web of Science) from January 2000 to March 2022. The metabolites involved were systematically examined and compared. Pathway analysis was conducted through the online software MetaboAnalyst 5.0.

Results

A total of 14 papers reporting 212 metabolites were included in this study. There were several highly reported metabolites: bile acids, such as glycocholic acid, taurochenodeoxycholic acid, taurocholic acid, tauroursodeoxycholic acid, and glycochenodeoxycholic acid. Dysregulation of metabolic pathways involved bile acid metabolism and lipid metabolism. Metabolites related to lipid metabolism include phosphatidylcholine, phosphorylcholine, phosphatidylserine, sphingomyelin, and ceramide.

Conclusions

This study provides a systematic review of metabolomics of ICP and deepens our understanding of the etiology of ICP.