Progesterone metabolites as farnesoid X receptor inhibitors

Relationship between cholestasis and altered progesterone metabolism in the placenta-maternal liver tandem

BACKGROUND

In intrahepatic cholestasis of pregnancy (ICP), there are elevated maternal serum levels of total bile acids, progesterone, and some sulfated metabolites, such as allopregnanolone sulfate, which inhibits canalicular function.

AIM

To investigate the relationship between cholestasis and the expression of crucial enzymes involved in progesterone metabolism in the liver and placenta.

METHODS

Obstructive cholestasis was induced by bile duct ligation (BDL). RT-qPCR (mRNA) and western blot (protein) were used to determine expression levels. Srd5a1 and Akr1c2 enzymatic activities were assayed by substrate disappearance (progesterone and 5α-dihydroprogesterone, respectively), measured by HPLC-MS/MS.

RESULTS

BDL induced decreased Srd5a1 and Akr1c2 expression and activity in rat liver, whereas both enzymes were up-regulated in rat placenta. Regarding sulfotransferases, Sult2b1 was also moderately up-regulated in the liver. In placenta from ICP patients, SRD5A1 and AKR1C2 expression was elevated, whereas both genes were down-regulated in liver biopsies collected from patients with several liver diseases accompanied by cholestasis. SRD5A1 and AKR1C2 expression was not affected by incubating human hepatoma HepG2 cells with FXR agonists (chenodeoxycholic acid and GW4064). Knocking-out Fxr in mice did not reduce Srd5a1 and Akr1c14 expression, which was similarly down-regulated by BDL.

CONCLUSION

SRD5A1 and AKR1C2 expression was markedly altered by cholestasis. This was enhanced in the placenta but decreased in the liver, which is not mediated by FXR. These results suggest that the excess of progesterone metabolites in the serum of ICP patients can involve both enhanced placental production and decreased hepatic clearance. The latter may also occur in other cholestatic conditions.

Increased Circulating Cortisol After Vaginal Birth Is Associated With Increased FGF19 Secretion in Neonatal Pigs

The influence of birth modality (scheduled cesarean or spontaneous vaginal) on the development of the newborn has been a source of controversy in neonatology. The impact of cesarean vs vaginal birth on the development of bile acid and fibroblast growth factor 19 (FGF19) signaling is unknown. Our aim was to determine the effect of birth modality and gestational age (preterm vs term) on plasma hormone levels, bile acid pool distribution, expression of genes in the bile acid-FXR-FGF19 pathway, and plasma levels of FGF19 at birth and on day 3 of life in neonatal pigs. Four sows underwent cesarean delivery on gestation day 105 (n = 2) and 114 (n = 2; term = 115 days), and 2 additional sows were allowed to farrow at term (gestation days 112 and 118). Piglets were euthanized at birth (Term-Vaginal n = 6; Term-Cesarean n = 8; Preterm n = 10) for tissue and blood collection, and the remaining pigs received total parenteral nutrition then were fed enterally on day 3 (Term-Vaginal n = 8; Term-Cesarean n = 10; Preterm n = 8), before blood and tissue were collected. Piglets born vaginally had a markedly (30-fold) higher plasma FGF19 at birth than term pigs born via cesarean delivery, and 70-fold higher than preterm pigs (P < 0.001). However, distal ileum FGF19 gene expression was similar in all groups (P > 0.05). Plasma FGF19 positively correlated with plasma cortisol (r = 0.58; P < 0.05) and dexamethasone treatment increased ileal FGF19 expression in cultured pig tissue explants and human enteroids. Our findings suggest that exposure to maternal or endogenous glucocorticoids in the perinatal period may upregulate the development of the bile acid-FGF19 pathway.

Impact of hepatitis B virus infection on maternal and infant outcomes of women with gestational diabetes mellitus: A three-year retrospective study

AIMS

To explore the impact of HBV infection on maternal and infant outcomes of GDM women.

METHODS

We retrospectively identified 8126 women with GDM in China from July 2017 to June 2020, and divided them into GDM with HBV infection group (n = 483) and GDM with non-HBV infection group (n = 7643). Two sample t-test and Chi-square test were used to compare differences between groups. Logistic regression models were used to explore the association between HBV infection and maternal and infant outcomes.

RESULTS

Placental abruption (PA), (2.3% vs. 1.0%, P = 0.008), placenta previa (4.3% vs. 2.8% p = 0.044), intrahepatic cholestasis of pregnancy (ICP), (6.4% vs. 3.0%, P < 0.001), cesarean section (52.0% vs. 46.0%, P = 0.011), fetal chromosomal abnormalities (1.2% vs. 0.4%, P = 0.021), and neonatal hyperglycemia (1.9% vs. 3.6%, P = 0.047) were more likely to occur in GDM with HBV infection group. After adjusting for the covariates, HBV infection was found to be associated with ICP (aOR, 2.35; 95% CI: [1.58-3.50]), PA (aOR, 2.34; 95% CI: 1.22-4.47), and fetal chromosomal abnormalities (aOR, 2.88; 95% CI: 1.18-7.03).

CONCLUSIONS

HBV infection was associated with part of maternal and infant outcomes in the GDM population.

Metabolic characteristics of plasma bile acids in patients with intrahepatic cholestasis of pregnancy-mass spectrometric study

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) is one of the more common complications in the middle and late stages of pregnancy, which requires early detection and intervention.

OBJECTIVE

The aim of the study is to investigate the changes in the metabolic profile of bile acids (BAs) in plasma of pregnant women with ICP and to look biomarkers for the diagnosis and grading of ICP, and to explore the disease mechanism.

METHODS

The targeted metabolomics based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze plasma BAs.

RESULTS

Twenty-seven BAs can be quantified in all participants. Among them, 22 BAs were identified as differential BAs between ICP and control groups. Five BAs include 3β-CA, 3β-DCA, CDCA-3Gln, NCA, and Tβ-MCA, were found to be associated with ICP for the first time. Nine BAs include NCA, GCA, GCDCA, GHCA, GUDCA, HCA, TCA, TCDCA and THCA, can be used as possible ICP diagnostic biomarkers. Four BAs, i.e., GLCA, THCA, GHCA and TLCA-3S may be used as potential biomarkers for ICP grading.

CONCLUSION

There were significant differences in plasma BA profiles between ICP patients and the control. The BA profiles of mild ICP group and severe ICP group partially overlapped. Potential diagnostic and grading BA markers were identified. A significant characteristic of ICP group was the increase of conjugated BAs. A mechanism to sustain the equilibrium of BA metabolism and adaptive response has been developed in ICP patients to accelerate excretion and detoxification.

Intrahepatic Cholestasis in Pregnancy: Review of the Literature

Intrahepatic cholestasis of pregnancy (ICP) is the most common hepatic disorder related to pregnancy in women. It usually develops within the third trimester of pregnancy and presents with pruritus as well as elevated levels of bile acid and/or alanine aminotransferase. Clinical signs quickly resolve after delivery; however, there is a high risk of the disorder recurring in subsequent pregnancies. ICP is associated with an increased risk of perinatal complications (premature birth, respiratory disorders, even stillbirth). Elevated levels of gestational hormones and genetic predispositions are important factors for the development of ICP; among the latter, mutations in hepatobiliary transport proteins (multidrug resistance protein 3-MDR3, bile salt export pump- BSEP) play a major role. Clinical and biochemical symptoms of ICP include pruritus and increased levels of total bile acids (TBA). Serum levels of TBA should be monitored in ICP patients throughout the pregnancy as concentrations above 40 μmol/L, which define that severe ICP isassociated with an increased risk of fetal complications. Therapeutic management is aimed at reducing the clinical symptoms, normalizing maternal biochemistry and preventing complications to the fetus. Pharmacological treatment of intrahepatic cholestasis of pregnancy consists of the administration of ursodeoxycholic acid to lower the levels of TBA and possibly reduce pruritus. If the treatment fails, premature delivery should be considered.

Targeting FXR in Cholestasis

The farnesoid X receptor (FXR, NR1H4) is a bile acid (BA)-activated transcription factor, which is essential for BA homeostasis. FXR and its hepatic and intestinal target genes, small heterodimer partner (SHP, NR0B2) and fibroblast growth factor 15/19 (Fgf15 in mice, FGF19 in humans), transcriptionally regulate BA synthesis, detoxification, secretion, and absorption in the enterohepatic circulation. Furthermore, FXR modulates a large variety of physiological processes, such as lipid and glucose homeostasis as well as the inflammatory response. Targeted deletion of FXR renders mice highly susceptible to cholic acid feeding resulting in cholestatic liver injury, weight loss, and increased mortality. Combined deletion of FXR and SHP spontaneously triggers early-onset intrahepatic cholestasis in mice resembling human progressive familial intrahepatic cholestasis (PFIC). Reduced expression levels and activity of FXR have been reported in human cholestatic conditions, such as PFIC type 1 and intrahepatic cholestasis of pregnancy. Recently, two pairs of siblings with homozygous FXR truncation or deletion variants were identified. All four children suffered from severe, early-onset PFIC and liver failure leading to death or need for liver transplantation before the age of 2. These findings underscore the central role of FXR as regulator of systemic and hepatic BA levels. Therefore, targeting FXR has been exploited in different animal models of both intrahepatic and obstructive cholestasis, and the first FXR agonist obeticholic acid (OCA) has been approved for the treatment of primary biliary cholangitis (PBC). Further FXR agonists as well as a FGF19 analogue are currently tested in clinical trials for different cholestatic liver diseases. This chapter will summarize the current knowledge on the role of FXR in cholestasis both in rodent models and in human diseases.

Expression and significance of dendritic cells and Th17/Treg in serum and placental tissues of patients with intrahepatic cholestasis of pregnancy

PURPOSE

Dendritic cells (DCs) are involved in immune system, which can also regulate the differentiation of T helper 17 (Th17) and regulatory T cells (Treg). DCs and Th17/Treg participate in preeclampsia and recurrent spontaneous abortion (RSA), but there is still lack of research in intrahepatic cholestasis of pregnancy (ICP). The aim was to evaluate the expression and significance of CD83+DCs, CD1a+DCs, interleukin-17 (IL-17) and IL-35 in serum and placental tissues of patients with ICP.

METHODS

Thirty cases of mild ICP, 25 cases of severe ICP were selected, and 30 cases of normal pregnant women were selected as control group. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) were used to detect the expression of CD83+DCs, CD1a+DCs, IL-17 and IL-35 in serum and placenta tissues, respectively.

RESULTS

There were more CD83+DCs, IL-17 expressed in placenta from women with ICP than in normal pregnancies, while the number of decidual CD1a+DCs, IL-35 was significantly lower in ICP than in normal pregnant women. The comparison within three groups had statistical difference (p < .05). Serum CD83+DCs and CD1a+DCs levels had no significance. IL-17 was higher in ICP, while IL-35 was lower.

CONCLUSIONS

DCs are involved in damaging the maternal-fetal immune tolerance by changing the phenotype and mature state, which may affect the differentiation of Th17/Treg to cause ICP.

Bile acids in drug induced liver injury: Key players and surrogate markers

Bile acid research has gained great momentum since the role of bile acids as key signaling molecules in the enterohepatic circulation was discovered. Their physiological function in regulating their own homeostasis, as well as energy and lipid metabolism make them interesting targets for the pharmaceutical industry in the context of diseases such as bile acid induced diarrhea, bile acid induced cholestasis or nonalcoholic steatohepatitis. Changes in bile acid homeostasis are also linked to various types of drug-induced liver injury (DILI). However, the key question whether bile acids are surrogate markers for monitoring DILI or key pathogenic players in the onset and progression of DILI is under intense investigation. The purpose of this review is to summarize the different facets of bile acids in the context of normal physiology, hereditary defects of bile acid transport and DILI.