Aromatase in human liver and its diseases

The Influence of Sex Hormones in Liver Function and Disease

The liver performs a multitude of bodily functions, whilst retaining the ability to regenerate damaged tissue. In this review, we discuss sex steroid biology, regulation of mammalian liver physiology and the development of new model systems to improve our understanding of liver biology in health and disease. A major risk factor for the development of liver disease is hepatic fibrosis. Key drivers of this process are metabolic dysfunction and pathologic activation of the immune system. Although non-alcoholic fatty liver disease (NAFLD) is largely regarded as benign, it does progress to non-alcoholic steatohepatitis in a subset of patients, increasing their risk of developing cirrhosis and hepatocellular carcinoma. NAFLD susceptibility varies across the population, with obesity and insulin resistance playing a strong role in the disease development. Additionally, sex and age have been identified as important risk factors. In addition to the regulation of liver biochemistry, sex hormones also regulate the immune system, with sexual dimorphism described for both innate and adaptive immune responses. Therefore, sex differences in liver metabolism, immunity and their interplay are important factors to consider when designing, studying and developing therapeutic strategies to treat human liver disease. The purpose of this review is to provide the reader with a general overview of sex steroid biology and their regulation of mammalian liver physiology.

Local aromatase excess with recruitment of unusual promoters of CYP19A1 gene in prepubertal patients with gynecomastia

OBJECTIVES

Gynecomastia may be due to aromatase excess in several diseases such as obesity and cancer. Aromatase excess syndrome (AEXS) is an autosomal dominant disorder caused by overexpression of CYP19A1. Germinal mutations occurring in AEXS include various genomic rearrangements including duplication, deletion, and inversion identified in the upstream region of CYP19A1. Aromatase overexpression caused by a CYP19A1 somatic mutation has been rarely described.

METHODS

Breast adipose tissue biopsies or surgical specimens were obtained from 19 subjects with gynecomastia. Aromatase quantification was performed by digital PCR and CYP19A1 sequencing by RACE PCR products.

RESULTS

We observed localized aromatase overexpression (>10 fold greater than normal) in breast adipose tissue from three prepubertal males with gynecomastia out of the 19 cases. One carried a chromosomal rearrangement between CYP19A1 and DMXL2, consistent with AEXS. In the 2 others, the first exon of CYP19A1 contained 11 different tissue-specific promoter subtypes, specifically I.4 or I.3 normally expressed by adipose tissue, but also the placental I.2 promoter and the more ubiquitous I.7 which is usually expressed in breast cancer, uterine, and endothelial tissues. No differences in clinical or biochemical characteristics were observed between these 3 subjects and 16 others without aromatase overexpression.

CONCLUSIONS

We describe two cases of aromatase overexpression in breast adipose tissue associated with nonspecific promoter recruitment. Further investigations are necessary to understand the mechanisms involved in aberrant promoter selection.

Add-On Selective Estrogen Receptor Modulators for Methadone Maintenance Treatment

Methadone maintenance treatment (MMT) remains the cornerstone for the management of opiate abuse. However, MMT can be associated with complex factors, including complications during the tolerance phase, the inability of some patients to maintain treatment effects during the tapering or abstinence phases, and the development of methadone dependence. Previous studies have revealed a sex disparity in MMT efficacy, showing that women undergoing MMT experiencing an increase in psychological symptoms compared with men and suggesting a link between disparate responses and the effects of estrogen signaling on methadone metabolism. More specifically, estradiol levels are positively associated with MMT dosing, and the expression of a single-nucleotide polymorphism (SNP) associated with estrogen receptor (ER) regulation is also associated with MMT dosing. In addition to performing mechanistic dissections of estrogen signaling in the presence of methadone, past studies have also proposed the targeting of estrogen signaling during MMT. The present report provides an overview of the relevant literature regarding sex effects, including differences in sex hormones and their potential impacts on MMT regimens. Moreover, this article provides a pharmacological perspective on the targeting of estrogen signals through the use of selective ER modulators (SERMs) during MMT. Preliminary preclinical experiments were also performed to evaluate the potential effects of targeting estrogen signaling with tamoxifen on methadone metabolism.

D-chiro-inositol, an aromatase down-modulator, increases androgens and reduces estrogens in male volunteers: a pilot study

BACKGROUND

Androgen deficiency affects men in the adulthood, causing several harmful effects at the reproductive and behavioural levels. Since aromatase is an enzyme that catalyses the conversion of androgens to estrogens, and it is responsible for an adequate balance of both sex hormones in males and females, the administration of molecules acting as down modulators may contribute to restore an abnormal enzymatic activity. A prospective pilot study was carried out to investigate the effect of D-chiro-inositol, a putative aromatase down-modulator, on serum levels of testosterone, estradiol, estrone, dehydroepiandrosterone and epiandrosterone from a group of adult male volunteers. Glucose, insulin, follicle-stimulating hormone, luteinizing hormone, inhibin B, D-chiro-inositol and myo-inositol serum levels were also measured.

RESULTS

Male volunteers were selected according to age and body mass index. Subjects with altered glycemia and/or hormonal status, due to advanced age or abnormal weight, were enrolled in the study. Each of the 10 volunteers enrolled took oral D-chiro-inositol (1 g/day) for 1 month. Serum assays of selected markers were performed at baseline (control) and after treatment. D-chiro-inositol administration was associated to reduced serum levels of estrone (- 85.0%) and estradiol (- 14.4%), and increased serum levels of testosterone (+ 23.4%) and dehydroepiandrosterone (+ 13.8%). In addition, epiandrosterone levels were higher (+39%) after treatment. On the other hand, follicle-stimulating hormone, luteinizing hormone and inhibin B did not change. A trend toward a decrease of glycemia, insulinemia and Homeostatic Model Assessment index was observed after D-chiro-inositol treatment, although differences did not reach statistical significance. D-chiro-inositol treatment did not cause any noticeable adverse effect.

CONCLUSIONS

Increased androgens and decreased estrogens seem to confirm that D-chiro-inositol acts as an aromatase down-modulator, but with a still unknown mechanism of action. This pilot study opens up new perspectives of research and therapeutic applications for D-chiro-inositol at different dosages and length of treatment. Authorization number 005/2020 released by the Local Ethics Committee of Alma Res Fertility Center, Rome.

TRIAL REGISTRATION NUMBER

NCT04615767 (registry: ClinicalTrials.gov) Date of registration: November 3, 2020.

Sex Differences in the Regulation of Vasopressin and Oxytocin Secretion in Bile Duct-Ligated Rats

INTRODUCTION

Hyponatremia due to elevated arginine vasopressin (AVP) secretion increases mortality in liver failure patients. No previous studies have addressed sex differences in hyponatremia in liver failure animal models.

OBJECTIVE

This study addressed this gap in our understanding of the potential sex differences in hyponatremia associated with increased AVP secretion.

METHODS

This study tested the role of sex in the development of hyponatremia using adult male, female, and ovariectomized (OVX) female bile duct-ligated (BDL) rats.

RESULTS

All BDL rats had significantly increased liver to body weight ratios compared to sham controls. Male BDL rats had hyponatremia with significant increases in plasma copeptin and FosB expression in supraoptic AVP neurons compared to male shams (all p < 0.05; 5-7). Female BDL rats did not become hyponatremic or demonstrate increased supraoptic AVP neuron activation and copeptin secretion compared to female shams. Plasma oxytocin was significantly higher in female BDL rats compared to female sham (p < 0.05; 6-10). This increase was not observed in male BDL rats. Ovariectomy significantly decreased plasma estradiol in sham rats compared to intact female sham (p < 0.05; 6-10). However, circulating estradiol was significantly elevated in OVX BDL rats compared to the OVX and female shams (p < 0.05; 6-10). Adrenal estradiol, testosterone, and dehydroepiandrosterone (DHEA) were measured to identify a possible source of circulating estradiol in OVX BDL rats. The OVX BDL rats had significantly increased adrenal estradiol along with significantly decreased adrenal testosterone and DHEA compared to OVX shams (all p < 0.05; 6-7). Plasma osmolality, hematocrit, copeptin, and AVP neuron activation were not significantly different between OVX BDL and OVX shams. Plasma oxytocin was significantly higher in OVX BDL rats compared to OVX sham.

CONCLUSIONS

Our results show that unlike male BDL rats, female and OVX BDL rats did not develop hyponatremia, supraoptic AVP neuron activation, or increased copeptin secretion compared to female shams. Adrenal estradiol might have compensated for the lack of ovarian estrogens in OVX BDL rats.

Disparate Effect of Aromatization on the Central Regulation of GH Secretion by Estrogens in Men and Postmenopausal Women

CONTEXT

Estrogen receptor antagonism by tamoxifen inhibits GH secretion in both men and postmenopausal women, suggesting that estrogen, albeit at low concentration, stimulates GH secretion. However, systemic estrogen replacement in postmenopausal women does not enhance GH secretion. To clarify the role of estrogen in mediating GH secretion, we investigated the effect of estrogen deprivation by using aromatase inhibitors.

AIM

To determine whether estrogens mediate GH secretion in men and postmenopausal women.

DESIGN

The effects of letrozole, an aromatase inhibitor, and tamoxifen were compared in an open-label crossover study. Eight men and 14 women received tamoxifen (20 mg/d) and letrozole (2.5 mg/d) for 2 weeks each. The primary endpoints were GH response to arginine stimulation and gonadal steroid levels.

RESULTS

In men, letrozole significantly (P < 0.05) reduced the peak GH response to arginine (mean ± SEM; Δ -49.4% ± 18.1%). Tamoxifen also reduced the mean peak GH, but this did not reach statistical significance. In postmenopausal women, letrozole did not affect peak GH, whereas tamoxifen significantly (P < 0.05) reduced peak GH (Δ -47.3% ± 10%). In men, letrozole reduced circulating estradiol (from 43.1 ± 2.8 to 12.7 ± 1.3 pmol/L; P < 0.001), whereas in women estradiol was undetectable (<11 pmol/L) at baseline and throughout letrozole therapy.

CONCLUSION

Because estrogen deprivation reduced circulating GH, we conclude that estrogens regulate GH secretion in men. In postmenopausal women, the neutral effect of aromatase inhibition is likely explained by pre-existing estrogen deficiency. The inhibition of GH secretion by tamoxifen in menopause suggests a non-estrogen receptor-mediated mechanism of action. In contrast to men, estrogen is unlikely to mediate GH secretion in postmenopausal women.

Hepatocyte-like cells derived from human amniotic epithelial, bone marrow, and adipose stromal cells display enhanced functionality when cultured on decellularized liver substrate

Transplantation of primary hepatocytes has been used in treatments for various liver pathologies and end-stage liver disease. However, shortage of donor tissue and the inability of hepatocyte proliferation in vitro have lead to alternative methods such as stem cell-derived hepatocyte-like cells (HLCs). Mesenchymal stromal/stem cells, and amniotic epithelial cells were isolated from human bone marrow (BM-MSCs), lipoaspirates (ASCs), and amniotic tissue (AECs) respectively. All cells were differentiated into HLCs on plates coated with Type I collagen or Porcine Liver Extracellular Matrix (PLECM-AA) matrix. Flow cytometry of BM-MSCs and ASCs, and AECs showed high expression of MSC-specific and embryonic stem cell markers respectively. All cell types differentiated into osteocytes, chondrocytes, and adipocytes. All cell type-derived HLCs presented the typical cuboidal primary hepatocyte morphology on PLECM-AA and fewer vacuoles (AECs) compared to HLCs cultured on type I collagen. Gene analysis of all cell type-derived HLCs cultured on PLECM-AA revealed higher upregulation of genes involved in drug transportation and metabolism compared to HLCs cultured on type I collagen. Although, HLCs cultured on PLECM-AA displayed some hepatocyte-related function and bioactivity, overall gene expression was lower compared to that of primary hepatocytes suggesting that caution should be taken when considering using HLCs to replace total hepatocyte functionality.

Abdominal and pelvic imaging findings associated with sex hormone abnormalities

Hormones are substances that serve as chemical communication between cells. They are unique biological molecules that affect multiple organ systems and play a key role in maintaining homoeostasis. In this role, they are usually produced from a single organ and have defined target organs. However, hormones can affect non-target organs as well. As such, biochemical and hormonal abnormalities can be associated with anatomic changes in multiple target as well as non-target organs. Hormone-related changes may take the form of an organ parenchymal abnormality, benign neoplasm, or even malignancy. Given the multifocal action of hormones, the observed imaging findings may be remote from the site of production, and may actually be multi-organ in nature. Anatomic findings related to hormone level abnormalities and/or laboratory biomarker changes may be identified with imaging. The purpose of this image-rich review is to sensitize radiologists to imaging findings in the abdomen and pelvis that may occur in the context of hormone abnormalities, focusing primarily on sex hormones and their influence on these organs.

Natural Compound Modulates the Cervical Cancer Microenvironment-A Pharmacophore Guided Molecular Modelling Approaches

Cervical cancer is regarded as one of the major burdens noticed in women next to breast cancer. Although, human papilloma viruses (HPVs) are regarded as the principal causative agents, they require certain other factors such as oestrogen hormone to induce cervical cancer. Aromatase is an enzyme that converts androgens into oestrogens and hindering this enzyme could subsequently hamper the formation of oestrogen thereby alleviating the disease. Accordingly, in the current investigation, a structure based pharmacophore was generated considering two proteins bearing the Protein Data Bank (PDB) codes 3EQM (pharm 1) and 3S7S (pharm 2), respectively. The two models were employed as the 3D query to screen the in-house built natural compounds database. The obtained 51 compounds were escalated to molecular docking studies to decipher on the binding affinities and to predict the quintessential binding modes which were affirmed by molecular dynamics (MD) simulations. The compound has induced dose-dependent down regulation of PP2B, Nitric oxide synthase-2 (NOS2), and Interleukin 6 (IL-6) genes in the HeLa cells and has modulated the expression of apoptotic genes such as Bax, Bcl2, and caspases-3 at different concentrations. These results guide us to comprehend that the identified aromatase inhibitor was effective against the cervical cancer cells and additionally could server as scaffolds in designing new drugs.

Porcine intestinal lymphoid tissues synthesize estradiol

Estradiol (17β-estradiol) is synthesized primarily in the gonads of both sexes and regulates the development and function of reproductive organs. Recently, we reported that intestinal lymphocyte homeostasis is regulated by estradiol synthesized de novo in the endothelial cells of the high endothelial venules (HEVs) of mesenteric lymph nodes and Peyer's patches in mice. This observation prompted us to hypothesize that HEVs of intestinal lymphoid tissues are sites of estradiol synthesis across species. In this study, we examined whether estradiol is synthesized in the intestinal lymphoid tissues of adolescent piglets. Comparisons of estradiol levels in blood and tissue showed that estradiol concentrations in mesenteric lymph nodes and Peyer's patches were significantly higher than the level in serum. Reverse transcription polymerase chain reaction showed that porcine intestinal lymphoid tissues express mRNAs for steroidogenic enzymes (StAR, 17β-Hsd,3β-Hsd, Cyp17a1, and Cyp19a1), and immunohistochemical results in ilial tissue showed expression of aromatase (CYP19) in Peyer's patch-localized endothelial cells of HEVs. When mesenteric lymph node and Peyer's patch tissues were cultured in vitro, they produced estradiol. Taken together, the results indicate that mesenteric lymph nodes and Peyer's patches are sites of estradiol synthesis in adolescent piglets.

Imbalanced expression pattern of steroid receptor coactivator-1 and -3 in liver cancer compared with normal liver: An immunohistochemical study with tissue microarray

Steroids affect normal and pathological functions of the liver through receptors, which require coactivators for their transcriptional activation. Steroid receptor coactivator (SRC)-1 and SRC-3 have been demonstrated to be regulated in numerous cancers; however, their expression profiles in liver cancer including hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC) remain unclear. Using tissue microarray immunohistochemistry, normal liver tissue and HCC tissue exhibited immunoreactivity of SRC-1, which were predominantly localized within extranuclear components; in CCC, they were detected within the cell nuclei; SRC-3 was also detected in the cell nuclei. Furthermore, no altered expression of SRC-1 and SRC-3 was observed in liver cancer compared with normal liver tissue; however, in CCC, the expression of SRC-3 was significantly increased compared with that detected in HCC. Importantly, although expression of SRC-1 and SRC-3 did not reveal any significant differences (30 vs. 40%) in normal liver tissue, HCC and CCC expression of SRC-1 was significantly decreased compared with that of SRC-3 (9.3 vs. 36%, and 6.7 vs. 67.7% for HCC and CCC, respectively). Further comparative analysis revealed that this discrepancy was detected in males with liver cancer, across all ages of HCC cases, younger CCC cases and all stages of liver cancer. The results suggested the presence of an imbalanced expression pattern of SRC-1 and SRC-3 from normal liver tissue to liver cancer (decreased SRC-1 and increased SRC-3), which may affect hepatic function and therefore promote liver carcinogenesis.

Aromatase in normal and diseased liver

Background A potential correlation between sex hormones, such as androgens and estrogens, and the development and progression of hepatocellular carcinoma (HCC) has been proposed. However, its details, in particular, aromatase status in diseased human liver has remained largely unknown. Materials and methods We immunolocalized aromatase, 17β-hydroxysteroid dehydrogenase (17β-HSD) type 1 and 17β-HSD type 2 in a total of 155 cases, consisting of normal liver (n = 10), nonalcoholic steatohepatitis (NASH) (n = 18), primary sclerosing cholangitis (PSC) (n = 6), primary biliary cholangitis (PBC) (n = 13), biliary atresia (n = 18), alcoholic hepatitis (n = 11), hepatitis C virus (HCV) (n = 31), HCV sustained virologic response (HCV-SVR) (n = 10), hepatitis B virus (HBV) (n = 20), HBV sustained virologic response (HBV-SVR) (n = 8) and infants (n = 10). Results Immunoreactivity scores of aromatase in HBV (59.5 ± 30.9), HBV-SVR (68.1 ± 33.5) and infants (100.5 ± 36.6) were significantly higher than those in normal liver (26.0 ± 17.1). Scores of 17β-HSD type 1 in any etiology other than HBV (116.3 ± 23.7) and infants (120.0 ± 28.5) were significantly lower than those in normal liver (122.5 ± 8.6). Scores of 17β-HSD type 2 in NASH (74.4 ± 36.6) were significantly lower than those in normal liver (128.0 ± 29.7). Conclusion High immunoreactivity scores of aromatase and 17β-HSD type 1 in the patients with HBV suggest a correlation between HBV infection and in situ estrogen synthesis in hepatocytes.

Sex steroids and the GH axis: Implications for the management of hypopituitarism

Growth hormone (GH) regulates somatic growth, substrate metabolism and body composition. Sex hormones exert profound effect on the secretion and action of GH. Estrogens stimulate the secretion of GH, but inhibit the action of GH on the liver, an effect that occurs when administered orally. Estrogens suppress GH receptor signaling by stimulating the expression proteins that inhibit cytokine receptor signaling. This effect of estrogens is avoided when physiological doses of estrogens are administered via a non-oral route. Estrogen-like compounds, such as selective estrogen receptor modulators, possess dual properties of inhibiting the secretion as well as the action of GH. In contrast, androgens stimulate GH secretion, driving IGF-1 production. In the periphery, androgens enhance the action of GH. The differential effects of estrogens and androgens influence the dose of GH replacement in patients with hypopituitarism on concomitant treatment with sex steroids. Where possible, a non-oral route of estrogen replacement is recommended for optimizing cost-benefit of GH replacement in women with GH deficiency. Adequate androgen replacement in conjunction with GH replacement is required to achieve the full anabolic effect in men with hypopituitarism.

Extra-gonadal sites of estrogen biosynthesis and function

Estrogens are the key hormones regulating the development and function of reproductive organs in all vertebrates. Recent evidence indicates that estrogens play important roles in the immune system, cancer development, and other critical biological processes related to human well-being. Obviously, the gonads (ovary and testis) are the primary sites of estrogen synthesis, but estrogens synthesized in extra- gonadal sites play an equally important role in controlling biological activities. Understanding non-gonadal sites of estrogen synthesis and function is crucial and will lead to therapeutic interventions targeting estrogen signaling in disease prevention and treatment. Developing a rationale targeting strategy remains challenging because knowledge of extra-gonadal biosynthesis of estrogens, and the mechanism by which estrogen activity is exerted, is very limited. In this review, we will summarize recent discoveries of extra-gonadal sites of estrogen biosynthesis and their local functions and discuss the significance of the most recent novel discovery of intestinal estrogen biosynthesis. [BMB Reports 2016; 49(9): 488-496]

Correlation between expression of CDC25A and Doppler ultrasound features in primary hepatocellular carcinoma

AIM: To investigate the expression of cell division cycle 25A (CDC25A) in primary hepatocellular carcinoma (PHC) and to explore its relationship with Doppler ultrasound imaging features.

METHODS: The expression of CDC25A in 86 PHC specimens and matched tumor-adjacent tissue specimens was detected by RT-PCR and Western blot. The imaging features of PHC was analyzed by Doppler ultrasound.

RESULTS: CDC25A was found to be overexpressed in 75.58% (65/86) of PHC cases (P < 0.05). The expression of CDC25A protein was significantly correlated with Doppler ultrasound imaging features including tumor size, blood flow grade, resistance index (RI) and portal vein invasion (all P < 0.05), but not with the number of liver tumor nodes (P > 0.05).

CONCLUSION: CDC25A may play an important role in the development and metastasis of PHC. Detection of CDC25A expression combined with ultrasound imaging may be used clinically for evaluation of treatment response and prognosis in PHC patients.