Bile acid stress in the mother and baby unit

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.

Current understanding of autophagy in intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is the most common liver disease during pregnancy. Manifested with pruritus and elevation in bile acids, the etiology of ICP is still poorly understood. Although ICP is considered relatively benign for the mother, increased rates of adverse fetal outcomes including sudden fetal demise are possible devastating outcomes associated with ICP. Limited understanding of the underlying mechanisms restricted treatment options and managements of ICP. In recent decades, evolving evidence indicated the significance of autophagy in pregnancy and pregnancy complications. Autophagy is an ancient self-defense mechanism which is essential for cell survival, differentiation and development. Autophagy has pivotal roles in embryogenesis, implantation, and maintenance of pregnancy, and is involved in the orchestration of diverse physiological and pathological cellular responses in patients with pregnancy complications. Recent advances in these research fields provide tantalizing targets on autophagy to improve the care of pregnant women. This review summarizes recent advances in understanding autophagy in ICP and its possible roles in the causation and prevention of ICP.

An enriched biosignature of gut microbiota-dependent metabolites characterizes maternal plasma in a mouse model of fetal alcohol spectrum disorder

Prenatal alcohol exposure (PAE) causes permanent cognitive disability. The enteric microbiome generates microbial-dependent products (MDPs) that may contribute to disorders including autism, depression, and anxiety; it is unknown whether similar alterations occur in PAE. Using a mouse PAE model, we performed untargeted metabolome analyses upon the maternal–fetal dyad at gestational day 17.5. Hierarchical clustering by principal component analysis and Pearson’s correlation of maternal plasma (813 metabolites) both identified MDPs as significant predictors for PAE. The majority were phenolic acids enriched in PAE. Correlational network analyses revealed that alcohol altered plasma MDP-metabolite relationships, and alcohol-exposed maternal plasma was characterized by a subnetwork dominated by phenolic acids. Twenty-nine MDPs were detected in fetal liver and sixteen in fetal brain, where their impact is unknown. Several of these, including 4-ethylphenylsulfate, oxindole, indolepropionate, p-cresol sulfate, catechol sulfate, and salicylate, are implicated in other neurological disorders. We conclude that MDPs constitute a characteristic biosignature that distinguishes PAE. These MDPs are abundant in human plasma, where they influence physiology and disease. Their altered abundance here may reflect alcohol’s known effects on microbiota composition and gut permeability. We propose that the maternal microbiome and its MDPs are a previously unrecognized influence upon the pathologies that typify PAE.

Can routine laboratory parameters predict adverse pregnancy outcomes in intrahepatic cholestasis of pregnancy?

AIM

Our aim was to investigate whether any hematological changes readily detectable by simple complete blood count (CBC), as well as fasting and postprandial total serum bile acid (SBA) levels, have diagnostic values for the prediction of adverse pregnancy outcomes in intrahepatic cholestasis of pregnancy (ICP).

METHODS

A prospective, case control study was carried out including 217 pregnant women (117 women with ICP and 100 healthy controls). The main outcome measures investigated were preterm delivery, APGAR scores, and neonatal unit admission. A multivariate logistic regression model was used to identify the independent risk factors of adverse pregnancy outcomes.

RESULTS

Compared with controls, women with ICP had significantly higher mean platelet volume (MPV) (mean 10.2±1.0 vs. 11.0±1.3; P<0.001) and platelet distribution width (PDW) (mean 13.1±2.3 vs. 14.7±2.8; P<0.001) values. Analysis with logistic regression revealed that the probability of preterm delivery did not increase until MPV levels exceeded 11.2 fL [odds ratio (OR)=2.68, 95% confidence interval (CI)=1.13-6.32, P=0.025], and total bilirubin levels exceeded 0.6 mg/dL (OR=3.13, 95% CI=1.21-8.09, P=0.019). Considering the low APGAR scores, only increased postprandial total SBA levels of ≥51 μmol/L were found to be predictive significantly (OR=3.02, 95% CI=1.07-8.53, P=0.037).

CONCLUSIONS

Our study suggests that increased MPV and total bilirubin levels are associated with preterm delivery, and increased postprandial total SBA levels are predictive for low APGAR in ICP patients.

Total bile acids in the maternal and fetal compartment in relation to placental ABCG2 expression in preeclamptic pregnancies complicated by HELLP syndrome

OBJECTIVE

To investigate total bile acid (TBA) levels in maternal (MB) and umbilical cord blood (UCB) in normotensive, preeclamptic (PE), and PE pregnancies complicated by hemolysis elevated liver enzymes and low platelets (HELLP) syndrome in the context of ABCG2 placental gene expression levels, a recently reported placental bile acid transporter.

METHODS

TBA levels were determined in 83 paired MB and UCB samples of normotensive, PE and PE/HELLP pregnancies and in 22 paired arterial and venous UCB samples from uncomplicated term pregnancies. ABCG2 gene expression was measured in 104 human placentas by reverse transcriptase quantitative polymerase chain reaction.

RESULTS

Overall, TBA levels in MB are higher compared to levels in UCB (p<0.0001), but this comparison looses statistical significance for the 11 PE/HELLP cases. TBA levels in maternal blood are increased in PE/HELLP compared to PE pregnancies (p=0.016). TBA levels in arterial and venous UCB from 22 normotensive pregnancies are not statistically different. ABCG2 expression is reduced in pregnancies where preeclampsia is further complicated by HELLP syndrome. ABCG2 expression in human placenta is not correlated with TBA levels in either the maternal or fetal compartment.

CONCLUSION

Increased maternal TBA levels in PE/HELLP pregnancies indicate a relation between bile acids in the maternal circulation and HELLP syndrome. As overall TBA levels in maternal blood are increased compared to UCB, we conclude that the placenta partly protects the fetus from increased maternal TBA levels. This consistent difference in TBA levels between the maternal and fetal compartment is unrelated to the placental expression of ABCG2.

Fetal lung surfactant and development alterations in intrahepatic cholestasis of pregnancy

AIM: To investigate the association between total bile acid (TBA) level during intrahepatic cholestasis of pregnancy (ICP) and fetal lung surfactant alteration.

METHODS: We recruited 42 ICP and 32 normal pregnancy women in this study. The maternal blood, fetal blood and amniotic fluid TBA level were detected using a circulating enzymatic method. Umbilical blood pulmonary surfactant protein A (SP-A) was evaluated with enzyme-linked immunosorbent assay. High performance liquid chromatography was used for the determination of phosphatidyl choline (PC), phosphatidyl inositol (PI), lysolecithin (LPC) and sphingomyelin (SM). Amniotic fluid lamellar body was counted with a fully automatic blood cell counter. Fetal lung area and fetal body weight were calculated from data obtained with an iu22 color supersonic diagnostic set. Clinical information of a nonstress test, amniotic fluid properties and neonatal Apgar score, and birth weight were recorded for review.

RESULTS: The TBA level in maternal blood, fetal blood and amniotic fluid in the ICP group were significantly higher than that in the control group (maternal blood: 34.11 ± 6.75 mmol/L vs 4.55 ± 1.72 mmol/L, P < 0.05; fetal blood: 11.9 ± 2.23 mmol/L vs 3.52 ± 1.56 mmol/L, P < 0.05; amniotic fluid: 3.89 ± 1.99 mmol/L vs 1.43 ± 1.14 mmol/L, P < 0.05). Amniotic fluid PC and PI in the ICP group were significantly lower than that in the control group (PC: 65.71 ± 7.23 μg/mL vs 69.70 ± 6.68 μg/mL, P < 0.05; PI: 3.87 ± 0.65 μg/mL vs 4.28 ± 0.74 μg/mL, P < 0.05). PC/LPC ratio of the ICP group was lower than that of the control group (14.40 ± 3.14 vs 16.90 ± 2.52, P < 0.05). Amniotic LB in the ICP group was significantly lower than that of the control group ((74.13 ± 4.37) × 10⁹/L vs (103.0 ± 26.82) × 10⁹/L, P < 0.05). Fetal umbilical blood SP-A level in the ICP group was significantly higher than that of the control group (30.26 ± 7.01 ng/mL vs 22.63 ± 7.42 ng/mL, P < 0.05). Fetal lung area/body weight ratio of the ICP group was significantly lower than that of the control group (5.76 ± 0.63 cm²/kg vs 6.89 ± 0.48 cm²/kg, P < 0.05). In the ICP group, umbilical cord blood TBA concentration was positively correlated to the maternal blood TBA concentration (r = 0.746, P < 0.05) and umbilical blood SP-A (r = 0.422, P < 0.05), but it was negatively correlated to the amniotic fluid lamellar corpuscle (r = 0.810, P < 0.05) and fetal lung area/body weight ratio (r = 0.769, P < 0.05). Furthermore, umbilical blood TBA showed a negative correlation to PC, SM and PI (r_pc = 0.536, r_sm = 0.438, r_pi = 0.387 respectively, P < 0.05). The neonatal asphyxia, neonatal respiratory distress syndrome, fetal distress and perinatal death rates in the ICP group are higher than that of the control group.

CONCLUSION: ICP has higher TBA in maternal and fetal blood and amniotic fluid. The high concentration of TBA may affect fetal pulmonary surfactant production and fetal lung maturation.

Effect of bile Acid on fetal lung in rat model of intrahepatic cholestasis of pregnancy

Objective. To determine the correlation between maternal bile acid (BA) level and fetal pulmonary surfactant in rats and study the effects of BA on fetal lung in rat model of intrahepatic cholestasis of pregnancy. Methods. Forty pregnant rats were treated with (A) 5.5 mg/kg BA, (B) 1.4 mg/kg BA, and (C) 1 ml physiological saline. Levels of total bile acid (TBA), ALT, AST, TBIL, DBIL, and SP-A were determined and the lungs of fetal rats were analyzed for pathological changes. Results. Groups A and B intervened with BA showed significant higher level of TBA in both maternal and fetal serum, more mortality rate of fetal rats, more concentration of SP-A in fetal serum, and wider alveolus mesenchyme of fetal rats than the control Group C. Higher level of BA associated with increased fetal risk and lower numerical density of mitochondria in type II alveolar epithelial cells. The levels of TBA in maternal serum were found to have significant positive correlation with those in fetal serum and SP-A level but negatively with the area of alveolus and the numerical density of lamellar body. Conclusions. The TBA level in maternal serum showed significant association with lung pathological changes in fetal rats.

Predicting fetal asphyxia in intrahepatic cholestasis of pregnancy

PURPOSE

Intrahepatic cholestasis of pregnancy (ICP) is a disease associated with high-perinatal morbidity and mortality rates. It is important to have parameters that aid in predicting fetal outcomes. Certain parameters affecting asphyxia in newborns to mothers with ICP are evaluated in this study.

METHODS

One hundred eighty-seven cholestatic pregnancies were analyzed, retrospectively. Fetal asphyxia was defined as an APGAR score of less than 7 at 5 min postpartum. Predictors of asphyxia in ICP were analyzed by binary multivariate logistic regression analysis.

RESULTS

Thirty-six of the cholestatic pregnancies ended up having an asphyctic newborn at the time of delivery (19.2%). There was a statistically significance difference in the levels of total bile acids (TBA) (42.4 +/- 15.2 vs. 33.8 +/- 12.9 micromol/L, P < 0.01), HDL cholesterol (54.2 +/- 15.9 vs. 61.3 +/- 12.2, P = 0.01), total cholesterol (279.0 +/- 51.4 vs. 257.7 +/- 51.6, P = 0.02), and triacylglycerol (299.4 +/- 94.6 vs. 260.4 +/- 118.7) between the asphytic and nonasphytic group. Binary multivariate logistic regression analysis demonstrated that TBA levels (OR 1.04, 95% CI 1.01-1.08, P = 0.03) and exposure time (OR 1.11, 95% CI 1.05-1.17, P < 0.01) were the most important independent variables predicting fetal asphyxia in ICP.

CONCLUSIONS

In this study, it has been demonstrated that for the evaluation of fetal status, increased TBA levels in the mother and increased exposure time for the fetus to these increased values of TBA within the maternal circulation system help to predict increased risk of asphyxia in newborns to ICP mothers.

Predicting respiratory distress syndrome in neonates from mothers with intrahepatic cholestasis of pregnancy

OBJECTIVE

Intrahepatic cholestasis of pregnancy (ICP) has been associated with prematurity and fetal mortality. Recently, ICP has also been recognised as a risk factor for neonatal respiratory distress syndrome (RDS) in term or near-term neonates. Since fetal mortality is more frequent in pregnancies with an early ICP onset, we speculated that the time of exposure (ET) to maternal bile acids at the delivery (BAdeliv) could be involved in neonatal lung damage too. Study aim was to develop a scoring system to predict the RDS occurrence.

DESIGN

We conducted a retrospective analysis of 77 pregnancies complicated by ICP (years 2000-2004) looking for factors associated to the neonatal RDS. We developed a risk score as follows: RDS risk score=BAdeliv x ET/gestational age and we prospectively applied it to 30 neonates from ICP pregnancies (years 2005-2006).

RESULTS

ROC analysis indicated 9 as the score with the highest sensitivity (83.3%) and specificity (87.5%). Considering a RDS incidence of about 25% in babies coming from ICP pregnancies, the post-test probability showed a risk increased to 66.7% with a score>9 and reduced to 4.8% with a score<or=9.

CONCLUSION

Our score is easy to apply and is based on the three most important variables involved in the RDS genesis. Score reliability is high enough to use it in clinical practice and to verify it in wider populations.

Intrahepatic cholestasis of pregnancy and neonatal respiratory distress syndrome

OBJECTIVES

We sought to verify the association between maternal intrahepatic cholestasis of pregnancy (ICP) and neonatal respiratory distress syndrome (RDS) and to determine how bile acids levels alter the risk of developing neonatal RDS.

METHODS

We extracted data from our divisional database about all of the newborns born during the years 2000-2004. We compared 77 neonates born from pregnancies complicated by ICP with 427 neonates in the same range of gestational age born from noncomplicated pregnancies. We studied maternal bile acids levels immediately before delivery in mothers with ICP and measured bile acid levels during the first 24 hours of life in their newborns.

RESULTS

The incidence of RDS in newborns from cholestatic pregnancies was twice that the reference population (28.6% vs 14%). The multivariate analysis showed that the risk of RDS in these newborns was approximately 2.5 times higher than in control infants. Within the ICP group, maternal and neonatal bile acid levels of infants affected by RDS were not significantly higher than those of healthy infants. The multivariate analysis showed that a low gestational age was the most important risk factor, but the probability of respiratory distress syndrome also increased by 2 per thousand for every additional micromole of the interaction term "neonatal by maternal bile acids level."

CONCLUSIONS

Maternal ICP is significantly associated with the occurrence of RDS in the newborn. We hypothesize that bile acids can produce surfactant depletion in the alveoli reverting the reaction of phospholipase A2. This hypothesis could potentially be confirmed by bronchoalveolar lavage study.

Developmental expression of aryl, estrogen, and hydroxysteroid sulfotransferases in pre- and postnatal human liver

Aryl- (SULT1A1), estrogen- (SULT1E1), and hydroxysteroid- (SULT2A1) sulfotransferases (SULTs) are active determinants of xenobiotic detoxication and hormone metabolism in the adult human liver. To investigate the role of these conjugating enzymes in the developing human liver, the ontogeny of immunoreactive SULT1A1, SULT1E1, and SULT2A1 expression was characterized in a series of 235 pre- and postnatal human liver cytosols ranging in age from early gestation to a postnatal age of 18 years. Interindividual variability in expression levels was apparent for all three SULTs in pre- and postnatal liver samples. Expression of the three SULTs displayed distinctly different developmental profiles. Semiquantitative Western blot analyses indicated that SULT1A1 and SULT2A1 immunoreactive protein levels were readily detectable in the majority of developmental human liver cytosols throughout the prenatal period. Whereas SULT1A1 expression did not differ significantly among the various developmental stages, SULT2A1 expression increased during the third trimester of gestation and continued to increase during postnatal life. By contrast, SULT1E1, a cardinal estrogen-inactivating enzyme, achieved the highest levels of expression during the earliest periods of gestation in prenatal male livers, indicating a requisite role for estrogen inactivation in the developing male. The present analysis suggests that divergent regulatory mechanisms are responsible for the differential patterns of hepatic SULT1A1, SULT1E1, and SULT2A1 immunoreactive protein levels that occur during pre- and postnatal human development, and implicates a major role for sulfotransferase expression in the developing fetus.

Cholestatic syndromes

PURPOSE OF REVIEW

This review highlights recent developments in the molecular pathogenesis of cholestasis as well new aspects of pathogenesis and management of clinical cholestatic disorders.

RECENT FINDINGS

Highlights include the role of nuclear receptors including FXR ligands as potential therapeutic agents, new genetic defects for pediatric cholestasis and sclerosing cholangitis, and novel infections and environmental agents as etiologies for primary biliary cirrhosis. Important clinical studies have been published in the area of pediatric cholestatic syndromes, intrahepatic cholestasis of pregnancy, primary biliary cirrhosis, primary and secondary sclerosing cholangitis, cholestasis of sepsis, viral cholestatic syndromes, and drug-induced cholestasis.

SUMMARY

These advances continue to improve understanding of the pathophysiology, diagnosis, and management of cholestatic liver disease.