Obeticholic acid improves fetal bile acid profile in a mouse model of gestational hypercholanemia

Gestational hypercholanemia suppresses pregnancy-associated adipose mass increase and stimulates a pro-inflammatory environment in mice

Women with intrahepatic cholestasis of pregnancy (ICP) have hypercholanemia alongside an increased risk of dyslipidemia. We investigated how cholic acid (CA) supplementation in murine pregnancy impacts adipose tissue function. Mice were fed normal or 0.5% CA-supplemented chow from identification of copulatory plug until gestational day 14 or 15 (n = 10-11/group) and were matched experimentally with nonpregnant mice (n = 7/group). Tissue weights were measured alongside plasma bile acids, glucose, lipids, reactive oxygen metabolites (ROM), and adipokines. Subcutaneous and gonadal adipocyte mRNA expression was evaluated. CA supplementation inhibited pregnancy-associated adipose tissue expansion and decreased fetal weight. CA diet in pregnancy increased LDL-cholesterol and reduced HDL-cholesterol. Pregnancy and CA diet reduced lipid metabolism transcript expression in adipocytes. CA supplementation during pregnancy increased plasma ROM by 1.24-fold and suppressed inflammatory-modulating pentraxin-2/3 and insulin-like growth factor 1 (IGF-1) levels by >50% and >80%, respectively. Together, we show that hypercholanemia disturbs pregnancy-associated adipose tissue expansion and mRNA expression in late gestation concomitant with reduced IGF-1, altered lipid availability and increased inflammation and oxidation, which could impact fetal growth. This work highlights the need to better understand adipose tissue and redox stress changes in ICP pregnancies and the potential implications for fetal health.

Obeticholic acid treatment of mice to promote fertilization and reproduction

Obeticholic acid (OCA), a farnesoid X receptor (FXR) agonist, has been demonstrated to ameliorate the histopathological characteristics of liver damage. Nonetheless, the systemic safety profile of OCA with regard to reproduction and development remains poorly understood. In the present study, we conducted a dose-response experiment by administering OCA at doses of 5 mg/kg, 10 mg/kg, or 20 mg/kg through tube feeding to investigate its effect on reproductive development and fertilization rate in both male and female mice. Furthermore, we evaluated the levels of protein and mitochondrial function in the placenta through western blot, qPCR, and scanning electron microscopy. The results showed that 10 mg/kg and 20 mg/kg OCA doses significantly reduced the rate of placental implantation (P < 0.05). Also, OCA increased maternal body weight. In addition, OCA increased levels of FXR and TGR5 and produced changes in oxidative stress levels (P < 0.05). Mitochondrial activity result found that 10 mg/kg and 20 mg/kg of OCA significantly reduced the mitophagy autosomes/nucleus compared with the normal control group (P < 0.05). What is more, there was no significant difference in sperm count after OCA intervention in either C57BL/10 mice or BALB/c mice. Overall, we demonstrated that OCA treatment protected against placental implantation by suppressing placental oxidative stress and mitochondrial activity.

Obeticholic acid alleviates intrauterine growth restriction induced by di-ethyl-hexyl phthalate in pregnant female mice by improving bile acid disorder

Di-(2-ethylhexyl)-phthalate (DEHP) is a ubiquitous environmental pollutant and is widely used in industrial plastics. Intrahepatic cholestasis of pregnancy (ICP), distinguished by maternal pruritus and elevated serum bile acid levels, is linked to unfavorable pregnancy consequences. Few studies have investigated the potential effect of gestational DEHP exposure on the cholestasis in pregnant female mice, and the underlying mechanisms remain unclear. In the present study, a mouse model of cholestasis during pregnancy was established by DEHP exposure. We found that DEHP induces elevated bile acid levels by affecting bile acid synthesis and transporter receptor expression in the maternal liver and placenta of pregnant female mice, ultimately leading to intrauterine growth restriction (IUGR). In addition, DEHP changed the bile acid composition of maternal serum and liver as well as placenta and amniotic fluid in pregnant female mice; Importantly, we found that DEHP down-regulates the expression of farnesoid X receptor (FXR), which is considered to be a bile acid receptor. FXR agonist obeticholic acid (OCA) effectively alleviated the adverse effects of DEHP on pregnant female mice. While, OCA itself had no adverse effects on normal pregnant female mice. In summary, DEHP could induces bile acid disorder and IUGR in pregnant female mice by affect FXR, which was reversed by OCA.

Hepatoprotective agents in the management of intrahepatic cholestasis of pregnancy: current knowledge and prospects

Intrahepatic cholestasis of pregnancy (ICP) is characterized by unexplained distressing pruritus in the mother and poses significant risk to the fetus of perinatal mortality. Occurring in the second and third trimester, the serum bile acid and aminotransferase are usually elevated in ICP patients. Ursodeoxycholic acid (UDCA) is the first line drug for ICP but the effectiveness for hepatoprotection is to a certain extent. In ICP patients with severe liver damage, combination use of hepatoprotective agents with UDCA is not uncommon. Herein, we reviewed the current clinical evidence on application of hepatoprotective agents in ICP patients. The underlying physiological mechanisms and their therapeutic effect in clinical practice are summarized. The basic pharmacologic functions of these hepatoprotective medications include detoxification, anti-inflammation, antioxidation and hepatocyte membrane protection. These hepatoprotective agents have versatile therapeutic effects including anti-inflammation, antioxidative stress, elimination of free radicals, anti-steatohepatitis, anti-fibrosis and anti-cirrhosis. They are widely used in hepatitis, non-alcoholic fatty liver disease, drug induced liver injury and cholestasis. Evidence from limited clinical data in ICP patients demonstrate reliable effectiveness and safety of these medications. Currently there is still no consensus on the application of hepatoprotective agents in ICP pregnancies. Dynamic monitoring of liver biochemical parameters and fetal condition is still the key recommendation in the management of ICP pregnancies.

Gut microbiota alters host bile acid metabolism to contribute to intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a female pregnancy-specific disorder that is characterized by increased serum bile acid and adverse fetal outcomes. The aetiology and mechanism of ICP are poorly understood; thus, existing therapies have been largely empiric. Here we show that the gut microbiome differed significantly between individuals with ICP and healthy pregnant women, and that colonization with gut microbiome from ICP patients was sufficient to induce cholestasis in mice. The gut microbiomes of ICP patients were primarily characterized by Bacteroides fragilis (B. fragilis), and B. fragilis was able to promote ICP by inhibiting FXR signaling via its BSH activity to modulate bile acid metabolism. B. fragilis-mediated FXR signaling inhibition was responsible for excessive bile acid synthesis and interrupted hepatic bile excretion to ultimately promote the initiation of ICP. We propose that modulation of the gut microbiota-bile acid-FXR axis may be of value for ICP treatment.

Alterations of the Human Gut Microbiota in Intrahepatic Cholestasis of Pregnancy

Background and Aims

Women with severe intrahepatic cholestasis of pregnancy (ICP) are at higher risks of fetal complications and without effective treatments. Changes in gut microbiota in pregnancy were found to be related to the altered intestinal bile acid composition, so we aimed to explore the alterations of microbiota in the gut of ICP patients.

Methods

A total of 90 women were recruited, including 45 ICP patients and 45 healthy controls. The gut microbiota communities of ICP group were compared to control group through 16S ribosomal RNA gene sequencing. The results were then confirmed by real-time polymerase chain reaction (PCR) and generalized linear model (GLM). Furthermore, we analyzed the relationships between microbiota and the severity of ICP.

Results

A total of seven genera and nine taxa with differential abundances between the ICP patients and the controls were identified. All of the seven genera were verified through real-time PCR, and three key genera Parabacteroides, Flavonifractor, and Megamonas were confirmed by using the GLM model. Further analysis found that the genera Escherichia_Shigella, Olsenella, and Turicibacter were enriched in the severe ICP group, the microbial gene function related to biosynthesis of unsaturated fatty acids and propanoate metabolism were also increased in them.

Conclusions

Overall, our study was the first in Asia to demonstrate an association between gut microbiota and ICP. Our findings would contribute to a better understanding of the occurrence of ICP.