Estrogens in intrahepatic cholestasis of pregnancy

Molecular Pathogenesis of Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease. The maternal symptoms are characterized by skin pruritus and elevated bile acids, causing several adverse outcomes for fetuses, including an increased risk of preterm birth, meconium-stained amniotic fluid, neonatal depression, respiratory distress syndrome, and stillbirth. Genetic, hormonal, immunological, and environmental factors contribute to the pathogenesis of ICP, and the estrogen-bile acid axis is thought to play a dominant role. The advances in the past 10 years uncover more details of this axis. Moreover, dysregulation of extracellular matrix and oxygen supply, organelle dysfunction, and epigenetic changes are also found to cause ICP, illuminating more potential drug targets for interfering with. Here, we summarize the molecular pathogenesis of ICP with an emphasis on the advancement in the past 10 years, aiming to give an updated full view of this field.

May circulating steroids reveal a predisposition to intrahepatic cholestasis of pregnancy in non-pregnant women?

Intrahepatic cholestasis of pregnancy (ICP) is a frequent liver disorder, mostly occurring in the third trimester. ICP is not harmful to the mothers but threatens the fetus. The authors evaluated steroid alterations in maternal and mixed umbilical blood to elucidate their role in the ICP development. Ten women with ICP were included in the study. Steroids in the maternal blood were measured by Gas Chromatography-Mass Spectrometry (GC-MS) (n=58) and RIA (n=5) at the diagnosis of ICP, labor, day 5 postpartum, week 3 postpartum and week 6 postpartum. The results were evaluated by ANOVA consisting of the subject factor, between subject factors ICP, gestational age at the diagnosis of ICP and gestational age at labor, within-subject factor Stage and ICP × Stage interaction. The 17 controls were firstly examined in the week 36 of gestation. ICP patients showed reduced CYP17A1 activity in the C17,20 lyase step thus shifting the balance between the toxic conjugated pregnanediols and harmless sulfated 5alpha/beta-reduced-17-oxo C19 steroids. Hence, more toxic metabolites originating in maternal liver from the placental pregnanes may penetrate backward to the fetal circulation. As these alterations persist in puerperium, the circulating steroids could be potentially used for predicting the predisposition to ICP even before next pregnancy.

The role of steroid hormones in the development of intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a disorder of liver function, commonly occurring in the third trimester but sometimes also as soon as the end of the second trimester of pregnancy. Symptoms of this disorder include pruritus, plus abnormal values of bile acids and hepatic transaminases. After birth, symptoms disappear and liver function returns to normal. Though ICP is relatively non-complicated and often symptomatically mild from the point-of-view of the mother, it presents a serious risk to the fetus, making this disease the subject of great interest. The etiology and pathogenesis of ICP is multifactorial and as yet not fully elucidated. Hormonal factors likely play a significant role, along with genetic as well as exogenous factors. Here we summarize the knowledge of changes in steroid hormones and their role in the development of intrahepatic cholestasis of pregnancy. In addition, we consider the role of exogenous factors as possible triggers of steroid hormone changes, the relationship between metabolic steroids and bile acids, as well as the combination of these factors in the development of ICP in predisposed pregnant women.

Toxic effect of pregnancy intrahepatic cholestasis on liver and placenta in pregnant rats

AIM: To investigate the toxic effect of intrahepatic cholestasis of pregnancy (ICP) on the liver and placenta in pregnant rats.

METHODS: The animal model of ICP was induced by 17-a-ethinylestradiol and progesterone. Pathohistological changes of the liver and placenta of the pregnant rats were observed under light and electronic microscope.

RESULTS: The levels of serum alanine transaminase (ALT), aspartate transaminase (AST), and total bile acid (TBA) were significantly higher in ICP rats than the control (AST: 3 784±155 vs 747±158; ALT: 7 076±220 vs 847±198; TBA: 78.5±4.5 vs 25.2±3.7; P<0.01 for all of the three). Granule- and vacuole-like cells were observed in liver of ICP rats under light microscope and Bile canaliculi were dilated and deposition of substances with high electronic density was found in bile canaliculi and hepatocytes of ICP rats by electronic microscopy. Granule- and vacuole-like changes were also found in some placenta syncytiotrophoblast of ICP rats by light microscopy.

CONCLUSION: ICP with hyperbileacidemia has marked toxicity to hepatocytes and placenta trophoblasts of pregnant rats.