Intrahepatic Cholestasis of Pregnancy: Natural History and Current Management

ABC transporters involved in respiratory and cholestatic diseases: From rare to very rare monogenic diseases

ATP-binding cassette (ABC) transporters constitute a 49-member superfamily in humans. These proteins, most of them being transmembrane, allow the active transport of an important variety of substrates across biological membranes, using ATP hydrolysis as an energy source. For an important proportion of these ABC transporters, genetic variations of the loci encoding them have been correlated with rare genetic diseases, including cystic fibrosis and interstitial lung disease (variations in CFTR/ABCC7 and ABCA3) as well as cholestatic liver diseases (variations in ABCB4 and ABCB11). In this review, we first describe these ABC transporters and how their molecular dysfunction may lead to human diseases. Then, we propose a classification of the genetic variants according to their molecular defect (expression, traffic, function and/or stability), which may be considered as a general guideline for all ABC transporters' variants. Finally, we discuss recent progress in the field of targeted pharmacotherapy, which aim to correct specific molecular defects using small molecules. In conclusion, we are opening the path to treatment repurposing for diseases involving similar deficiencies in other ABC transporters.

Early-onset intrahepatic cholestasis of pregnancy increased the incidence of gestational diabetes mellitus: a retrospective cohort study

Background

Intrahepatic cholestasis of pregnancy (ICP) and gestational diabetes mellitus (GDM) are two common pregnancy complications that pose considerable health challenges. The interplay between these conditions is believed to significantly influence pregnancy outcomes, yet the nature of this relationship remains elusive. This study was designed to elucidate the connection between ICP and GDM.

Methods

This retrospective cohort study included 742 singleton pregnancies delivered at the Shanghai Public Health Clinical Center from January 2015 to December 2023. We compared the incidence of GDM and pregnancy outcomes between multiple ICP subgroups and a control group of healthy pregnancies. A multivariate regression model was used to measure the independent association between ICP and propensity for GDM development, as well as to assess the impact of potential bidirectional effects between ICP and GDM.

Results

The results indicate that the incidence of GDM is highest in the early-onset ICP (diagnosed before the 24th week of gestation) group compared to the control group and other ICP subgroups. Early-onset ICP is an independent risk factor for the development of GDM, with other risk factors including age, history of abortion, family history of diabetes, and elevated ALT levels. Subgroup interaction analysis did not reveal heterogeneity in the influence of early-onset ICP on the development of GDM across different subgroups. Further analysis showed that GDM itself does not increase the risk of late-onset ICP. Additionally, when comparing pregnancy outcomes between GDM patients with or without ICP, those with both GDM and ICP had significantly higher rates of preterm birth, cesarean section, and small for gestational age (SGA) compared to patients with GDM alone. Furthermore, elevated TBA levels (first diagnosed) of early-onset ICP patients were associated with an increased risk of GDM in a nonlinear fashion.

Conclusion

Our study indicated that early-onset ICP is significantly linked to an increased risk of GDM. Further research is warranted to explore the mechanisms behind this association and to develop strategies for early identification and intervention to mitigate GDM risk.

Core biomarkers analysis benefit for diagnosis on human intrahepatic cholestasis of pregnancy

BACKGROUND

The pregnant women with intrahepatic cholestasis were at high risk of fetal distress, preterm birth and unexpected stillbirth. Intrahepatic cholestasis of pregnancy (ICP) was mainly caused by disorder of bile acid metabolism, whereas the specific mechanism was obscure.

METHODS

We performed proteomics analysis of 10 ICP specimens and 10 placenta specimens from patients without ICP through data-independent acquisition (DIA) technique to disclose differentially expressed proteins. We executed metabolomic analysis of 30 ICP specimens and 30 placenta specimens from patients without ICP through UPLC-MS/MS to identify differentially expressed metabolites. Enrichment and correlation analysis was used to obtain the direct molecular insights of ICP development. The ICP rat models were constructed to validate pathological features.

RESULTS

The heatmap of proteomics analysis showed the top 30 up-regulated and 30 down-regulated proteins. The metabolomic analysis revealed 20 richer and 4 less abundant metabolites in ICP samples compared with placenta specimens from patients without ICP, and enrichment pathways by these metabolites included primary bile acid biosynthesis, cholesterol metabolism, bile secretion, nicotinate and nicotinamide metabolism, purine metabolism and metabolic pathways. Combined analysis of multiple omics results demonstrated that bile acids such as Glycohyocholic acid, Glycine deoxycholic acid, beta-Muricholic acid, Noncholic acid, cholic acid, Gamma-Mercholic Acid, alpha-Muricholic acid and Glycochenodeoxycholic Aicd were significantly associated with the expression of GLRX3, MYL1, MYH7, PGGT1B, ACTG1, SP3, LACTB2, C2CD5, APBB2, IPO9, MYH2, PPP3CC, PIN1, BLOC1S1, DNAJC7, RASAL2 and ATCN3 etc. The core protein ACAT2 was involved in lipid metabolic process and animal model showed that ACAT2 was up-regulated in placenta and liver of pregnant rats and fetal rats. The neonates had low birth weight and Safranin O-Fast green FCF staining of animal models showed that poor osteogenic and chondrogenic differentiation of fetal rats.

CONCLUSION

Multiple metabolites-alpha-Muricholic acid, beta-Muricholic acid, Glycine deoxycholic acid and Glycochenodeoxycholic Acid etc. were perfect biomarkers to predict occurrence of ICP. Bile acids were significantly associated with varieties of protein expression and these proteins were differentially expressed in ICP samples. Our study provided several biomarkers for ICP detection and potential therapeutic targets for ICP development.

Proteomic Biomarkers of Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease, which can lead to adverse fetal outcomes, including preterm labor and intrauterine death. The pathogenesis of ICP is still unclear. We hypothesized that pathological index leads to abnormal placenta changes in ICP. Investigation of these differences in protein expression in parallel profiling is essential to understand the comprehensive pathophysiological mechanism underlying ICP. The present study screened differentially expressed proteins (DEPs) as novel diagnostic markers for ICP. Proteomic profiles of placental tissues from 32 ICP patients and 24 healthy volunteers (controls) were analyzed. Our founding was valid by following western blotting and immunohistochemistry staining, respectively. The association of the key protein expression with clinicopathological features of ICP was further analyzed. A total of 178 DEPs were identified between the ICP and control groups. Functional enrichment analysis showed these proteins were significantly enriched in the PPAR singling pathway by KEGG and PPARα/RXRα activation by IPA. Apolipoprotein A2 (APOA2) was the only upregulated protein, which uniquely identified in ICP groups and related to both pathways. Validation of western blotting and immunohistochemical staining analysis showed significantly higher APOA2 expression in the ICP group than in the control group. Furthermore, the expression of APOA2 is associated with clinicopathological features in ICP groups. Receiver operating characteristic (ROC) curve analyses showed that the AUC of APOA2 was 0.8984 (95% confidence interval (CI): 0.772-1.000). This study has identified up-regulated APOA2 associated with PPAR singling pathway and PPARα/RXRα activation in ICP. Thus, APOA2 may be involved in ICP pathogenesis, serving as a novel biomarker for its diagnosis.

Ursodeoxycholic acid and 18β-glycyrrhetinic acid alleviate ethinylestradiol-induced cholestasis via downregulating RORγt and CXCR3 signaling pathway in iNKT cells

Estrogen-induced intrahepatic cholestasis (IHC) is a mild but potentially serious risk and urges for new therapeutic targets and effective treatment. Our previous study demonstrated that RORγt and CXCR3 signaling pathway of invariant natural killer T (iNKT) 17 cells play pathogenic roles in 17α-ethinylestradiol (EE)-induced IHC. Ursodeoxycholic acid (UDCA) and 18β-glycyrrhetinic acid (GA) present a protective effect on IHC partially due to their immunomodulatory properties. Hence in present study, we aim to investigate the effectiveness of UDCA and 18β-GA in vitro and verify the accessibility of the above targets. Biochemical index measurement indicated that UDCA and 18β-GA presented efficacy to alleviate EE-induced cholestatic cytotoxicity. Both UDCA and 18β-GA exhibited suppression on the CXCL9/10-CXCR3 axis, and significantly restrained the expression of RORγt in vitro. In conclusion, our observations provide new therapeutic targets of UDCA and 18β-GA, and 18β-GA as an alternative treatment for EE-induced cholestasis.

Secreted proteins in plasma and placenta as novel non-invasive biomarkers for intrahepatic cholestasis of pregnancy: A case-control study

Background

Intrahepatic cholestasis of pregnancy (ICP) is likely to lead to unfavorable consequences. Total bile acid (TBA) is thought to be the sole ICP indicator available as of now, but it comes with some kind of restrictions in terms of sensitivity and specificity. We were endeavoring to find potential diagnostic biomarkers for ICP in this investigation.

Methods

This case-control study with a prospective nature included 40 females in the stage of pregnancy who were diagnosed with ICP. It also included another 20 females who were also pregnant but with sound physical condition(control). Placental and plasma samples were collected from all females that were in the stage of pregnancy, except for 20 ICP patients, in which only plasma was collected. We used four-dimensional data-independent acquisition followed by enzyme-linked immunosorbent assay and immunohistochemistry to identify and validate plasma and placental profiles in ICP patients and controls. Bioinformatics was adopted in an effort to demonstrate the relevant biological processes and signalling pathways. Correlation analysis was used to analyse the consistency of tissue and plasma protein expression and the correlation between sequencing and experimental results.

Results

The expression levels of nectin-1 (NECTIN1), Kunitz-type protease inhibitor 1 (SPINT1), and inter-alpha-trypsin inhibitor heavy chain H3 (ITIH3) were remarkably higher in ICP patients than in controls. However, heparin cofactor 2 (SERPIND1) expression levels in female participants in the stage of pregnancy who were diagnosed with ICP were remarkably lower than those pregnant females with good physical fitness. In addition to the negative correlation between SERPIND1 and TBA, NECTIN1, SPINT1, and ITIH3 expression positively correlated with TBA. Area under the receiver operating characteristic curve (AUC) values of 0.7925, 0.8313, 0.8163, and 0.9025, respectively, were used to assess the diagnostic accuracies of NECTIN1, SPINT1, ITIH3, and SERPIND1. AUC (0.9438) was considerably greater when NECTIN1, SPINT1, and SERPIND1 were integrated, according to binary logistic regression. The AUC of the ROC curve for various combinations of SERPIND1 and other indicators was higher than itself, thus providing a more reliable ICP diagnosis. Furthermore, according to the bioinformatics analysis, the NECTIN1, SPINT1, ITIH3, and SERPIND1 were identified as secreted proteins because they were localized in the extracellular region.

Conclusions

This research discovered new non-invasive ICP indicators. On top of this, it sheds new light on the crucial diagnostic function of secreted proteins in ICP.

Intrahepatic cholestasis of pregnancy - Diagnosis and management: A consensus statement of the Society of Obstetric Medicine of Australia and New Zealand (SOMANZ): Executive summary

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy liver disease, characterised by pruritus and increased total serum bile acids (TSBA), Australian incidence 0.6-0.7%. ICP is diagnosed by non-fasting TSBA ≥19 μmol/L in a pregnant woman with pruritus without rash without a known pre-existing liver disorder. Peak TSBA ≥40 and ≥100 μmol/L identify severe and very severe disease respectively, associated with spontaneous preterm birth when severe, and with stillbirth, when very severe. Benefit-vs-risk for iatrogenic preterm birth in ICP remains uncertain. Ursodeoxycholic acid remains the best pharmacotherapy preterm, improving perinatal outcome and reducing pruritus, although it has not been shown to reduce stillbirth.

Causal association between gut microbiota and intrahepatic cholestasis of pregnancy: mendelian randomization study

BACKGROUND

Previous observational cohort studies have shown that the composition of the gut microbiota is related to the risk of intrahepatic cholestasis of pregnancy (ICP), although it is unclear if the association is causative. This study used Mendelian randomization (MR) to systematically examine whether the gut microbiota was causally linked to ICP.

METHODS

We obtained the genome-wide association study (GWAS) summary statistics of gut microbiota and ICP from published GWASs. Maximum likelihood (ML), MR-Egger regression, weighted median, inverse variance weighted (IVW), and weighted model were used to investigate the causal association between gut microbiota and ICP. We further conducted a series of sensitivity analyses to confirm the robustness of the primary results of the MR analyses. Reverse MR analysis was performed on the bacterial taxa that were reported to be causally linked to ICP risk in forwarding MR analysis to evaluate the possibility of reverse causation.

RESULTS

MR analysis revealed that phylum Tenericutes (OR: 1.670, 95%CI: 1.073-2.598, P = 0.023), class Bacteroidia (OR: 1.644, 95%CI: 1.031-2.622, P = 0.037), class Mollicutes (OR: 1.670, 95%CI: 1.073-2.598, P = 0.023), and order Bacteroidales (OR: 1.644, 95%CI: 1.031-2.622, P = 0.037), and were positively associated with the risk of ICP. And we identified that the relative abundance of genus Dialister (OR: 0.562, 95%CI: 0.323-0.977, P = 0.041), genus Erysipelatoclostridium (OR: 0.695, 95%CI: 0.490-0.987, P = 0.042), genus Eubacterium (brachy group) (OR: 0.661, 95%CI: 0.497-0.880, P = 0.005), genus Eubacterium (hallii group) (OR: 0.664, 95%CI: 0.451-0.977, P = 0.037), genus Holdemania (OR: 0.590, 95%CI: 0.414-0.840, P = 0.003), genus Ruminococcus (torques group) (OR: 0.448, 95%CI: 0.235-0.854, P = 0.015), and genus Veillonella (OR: 0.513, 95%CI: 0.294-0.893, P = 0.018) were related to a lower risk of ICP. Additional sensitivity analyses confirmed the robustness of the association between specific gut microbiota composition and ICP. No evidence of reverse causality from ICP to identified bacterial taxa was found in the findings of the reverse MR analyses.

CONCLUSIONS

Under MR assumptions, our findings propose new evidence of the relationship between gut microbiota and ICP risk. Our results show that the gut microbiota may be useful target of intervention for ICP.

SWATH proteomics analysis of placental tissue with intrahepatic cholestasis of pregnancy

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) usually occurs in the second and third trimesters. The disease's etiology and diagnostic criteria are currently unknown. Based on a sequence window to obtain all theoretical fragment ions (SWATH) proteomic approach, this study sought to identify potential proteins in placental tissue that may be involved in the pathogenesis of ICP and adverse fetal pregnancy outcomes.

METHODS

The postpartum placental tissue of pregnant women with ICP were chosen as the case group (ICP group) (subdivided into mild ICP group (MICP group) and severe ICP group (SICP group)), and healthy pregnant women were chosen as the control group (CTR). The hematoxylin-eosin (HE) staining was used to observe the histologic changes of placenta. The SWATH analysis combined with liquid chromatography-tandem mass spectrometry (LC-MS) was used to screen the differentially expressed proteins (DEPs) in ICP and CTR groups, and bioinformatics analysis was used to find out the biological process of these differential proteins.

RESULTS

Proteomic studies showed there were 126 DEPs from pregnant women with ICP and healthy pregnant women. Most of the identified proteins were functionally related to humoral immune response, cell response to lipopolysaccharide, antioxidant activity and heme metabolism. A subsequent examination of placentas from patients with mild and severe ICP revealed 48 proteins that were differentially expressed. Through death domain receptors and fibrinogen complexes, these DEPs primarily regulate extrinsic apoptotic signaling pathways, blood coagulation, and fibrin clot formation. The differential expressions of HBD, HPX, PDE3A, and PRG4 were down-regulated by Western blot analysis, which was consistent with proteomics.

DISCUSSION

This preliminary study helps us to understand the changes in the placental proteome of ICP patients, and provides new insights into the pathophysiology of ICP.

Cholestasis: exploring the triangular relationship of gut microbiota-bile acid-cholestasis and the potential probiotic strategies

Cholestasis is a condition characterized by the abnormal production or excretion of bile, and it can be induced by a variety of causes, the factors of which are extremely complex. Although great progress has been made in understanding cholestasis pathogenesis, the specific mechanisms remain unclear. Therefore, it is important to understand and distinguish cholestasis from different etiologies, which will also provide indispensable theoretical support for the development of corresponding therapeutic drugs. At present, the treatment of cholestasis mainly involves several bile acids (BAs) and their derivatives, most of which are in the clinical stage of development. Multiple lines of evidence indicate that ecological disorders of the gut microbiota are strongly related to the occurrence of cholestasis, in which BAs also play a pivotal role. Recent studies indicate that probiotics seem to have certain effects on cholestasis, but further confirmation from clinical trials is required. This paper reviews the etiology of and therapeutic strategies for cholestasis; summarizes the similarities and differences in inducement, symptoms, and mechanisms of related diseases; and provides information about the latest pharmacological therapies currently available and those under research for cholestasis. We also reviewed the highly intertwined relationship between gut microbiota-BA-cholestasis, revealing the potential role and possible mechanism of probiotics in the treatment of cholestasis.

Prevalence, risk factors and adverse perinatal outcomes for Chinese women with intrahepatic cholestasis of pregnancy: a large cross-sectional retrospective study

BACKGROUND

Intrahepatic cholestasis of pregnancy (ICP) is the most common pregnancy-related liver disorder and may cause adverse perinatal outcomes. This large cross-sectional retrospective study aimed to evaluate the prevalence and related risk factors of ICP and determine the adverse perinatal outcomes.

METHODS

This large cohort study from 1 January 2018 to 31 December 2019, included 39,742 eligible pregnant women. Data were extracted from the institutional electronic medical record database and analyzed using univariate and multivariate logistic regression models to determine the risk factors and adverse perinatal outcomes of ICP.

RESULTS

The overall prevalence of ICP was 3.81%. It was significantly higher in hepatitis B surface antigen (HBsAg) positive than negative women in all age groups, and in women with pre-pregnancy BMI underweight and obesity aged <25 years and ≥35 years than the other age groups. Multivariate logistic regression models showed an increased risk of ICP associated with maternal age <25 years and ≥35 years, pre-pregnancy underweight and obesity, HBsAg positive status, twin pregnancies, low maternal education, inadequate gestational weight gain, multiparous, in vitro fertilization, caesarean section history and the number of abortions ≥2. The presence of ICP was associated with increased risk of maternal outcomes of caesarean section and preterm birth, and neonatal outcomes of low birth weight and neonatal unit admission in singleton and twin pregnancies.

CONCLUSION

This study identified the prevalence, possible risk factors, and associated adverse perinatal outcomes of ICP, which provides useful information for clinicians to identify, counsel, and provide timely management for women at risk.KEY MESSAGESMaternal age <25 and ≥35, pre-pregnancy BMI underweight and obesity, hepatitis B surface antigen-positive status, twin pregnancies, low maternal education, inadequate gestational weight gain, multiparous, in vitro fertilization, caesarean section history and the number of abortions ≥2 are associated with an increased risk of ICP.Further, pregnancies with ICP are associated with an increased risk of maternal outcomes of caesarean section and preterm birth and neonatal outcomes of low birth weight and neonatal unit admission in singleton and twin pregnancies.

Comprehensive Analysis of Quantitative Proteomics With DIA Mass Spectrometry and ceRNA Network in Intrahepatic Cholestasis of Pregnancy

Background: Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific complication characterized by pruritus without skin damage and jaundice. The poor perinatal outcomes include fetal distress, preterm birth, and unexpected intrauterine death. However, the mechanism of ICP leading to poor prognosis is still unclear.

Methods: We analyzed 10 ICP and 10 normal placental specimens through quantitative proteomics of data-independent acquisition (DIA) to screen and identify differentially expressed proteins. GO, KEGG, COG/KOG, StringDB, InterProScan, Metascape, BioGPS, and NetworkAnalyst databases were used in this study. PITA, miRanda, TargetScan, starBase, and LncBase Predicted v.2 were used for constructing a competing endogenous RNA (ceRNA) network. Cytoscape was used for drawing regulatory networks, and cytoHubba was used for screening core nodes. The ICP rat models were used to validate the pathological mechanism.

Results: GO, KEGG, and COG/KOG functional enrichment analysis results showed the differentially expressed proteins participated in autophagy, autophagosome formation, cofactor binding, JAK-STAT signaling pathway, and coenzyme transport and metabolism. DisGeNET analysis showed that these differentially expressed proteins were associated with red blood cell disorder and slow progression. We further analyzed first 12 proteins in the upregulated and downregulated differentially expressed proteins and incorporated clinicopathologic parameters. Our results showed HBG1, SPI1, HBG2, HBE1, FOXK1, KRT72, SLC13A3, MBD2, SP9, GPLD1, MYH7, and BLOC1S1 were associated with ICP development. ceRNA network analysis showed that MBD2, SPI1, FOXK1, and SLC13A3 were regulated by multiple miRNAs and lncRNAs.

Conclusion: ICP was associated with autophagy. The ceRNA network of MBD2, SPI1, FOXK1, and SLC13A3 was involved in ICP progression, and these core proteins might be potential target.

Research progress in the role of gut microbiota and its metabolites in intrahepatic cholestasis of pregnancy

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) is a liver disease that occurs during pregnancy. While ICP has a minimal impact on the mother, it primarily affects the pregnancy outcome of fetus, resulting in spontaneous miscarriage and even the intrauterine death of fetus.

AREAS COVERED

This review covers current progress in the role of gut microbiota and bile acids in ICP.

EXPERT OPINION

The causes and pathogenesis of ICP are currently unclear, and the serum bile acid level is the main clinical evidence for ICP diagnosis. The gastrointestinal tract is home to a tremendous number and type of microbes, which play critical roles in the synthesis and metabolism of bile acids. Studies in recent years have shown that the changes in gut microbiota and bile acid metabolic profiles are closely associated with ICP. This review discusses some of the future prospects in this area of research.