Expression and cyclic variations of catechol-O-methyl transferase in human endometrial stroma

The role of estrogen metabolites in human ovarian function

Estrogens produced by the ovary play diverse roles in controlling physiological changes in the function of the female reproductive system. Although estradiol acts through classical nuclear receptors, its metabolites (EMs) act by alternative pathways. It has been postulated that EMs act through paracrine-autocrine pathways to regulate key processes involved in normal follicular growth, corpus luteum (CL) development, function, and regression. The present review describes recent advances in understanding the role of EMs in human ovarian physiology during the menstrual cycle, including their role in anovulatory disorders and their action in other target tissues.

Endometrial safety of low-dose vaginal estrogens

ABSTRACT

It is estimated that up to 50% to 90% of postmenopausal women may experience genitourinary syndrome of menopause (GSM), which may have a detrimental impact on quality of life. One of the most effective modes of treatment of GSM is low-dose vaginal estrogens. Numerous studies have addressed the safety of these estrogens using endometrial biopsy and/or endometrial thickness on ultrasound. Based on these studies, the consensus is that low-dose vaginal estrogens do not substantially increase the risk of endometrial hyperplasia or cancer; however, the data are severely limited by short duration of follow-up. Although long-term trials are warranted, they are difficult to carry out, costly, and will not yield data for years. More immediate information regarding endometrial safety may be obtained from studies measuring endometrial tissue and serum concentrations of estradiol, estrone, and relevant equine estrogens after administration of different estrogen formulations and doses. This would allow us to understand better the metabolism of estrogens by the vagina and endometrium, and how much estrogen is reaching the endometrium. Here, we discuss metabolism, receptor binding, and signaling of estrogens in vaginal and endometrial tissue, and summarize the existing studies on the endometrial impact of low-dose vaginal estrogen treatment in postmenopausal women.

Variation in the Methylation of Caffeoylquinic Acids and Urinary Excretion of 3'-methoxycinnamic acid-4'-Sulfate After Apple Consumption by Volunteers

INTRODUCTION

It has been reported that the phenolic metabolite 3'-methoxycinnamic acid-4'-sulfate generated from 5-O-caffeoylquinic acid may have potential benefits in human health. However, the variation in 3'- and 4'-methylation of 3',4'-dihydroxycinnamic acid and its impact on the yield of this sulfate metabolite is unclear and has been poorly studied.

METHODS AND RESULTS

To address this aim, the excreted 3'-methoxy and 4'-methoxy metabolites in urine samples (24-h) are determined in 14 volunteers after an acute intake of 80 g of red-fleshed apple (RFA) or white-fleshed apple (WFA). These methoxy metabolites are also determined in the same volunteers in a second acute intake after a 6-week sustained consumption of the same products.

CONCLUSION

Seven 3'-methoxy and seven 4'-methoxy metabolites are determined, i.e., the free cinnamic and corresponding phenylpropanoic acid, plus their sulfate, glucuronide, and glycine conjugates. In only six volunteers, five females and one male, is 4'-methylation preferred over 3'-methylation, but it is observed that an individual's 3'- : 4'-methylation ratio can change over time, and that the yield of 3'-methoxycinnamic acid-4'-sulfate is extremely variable, ranging from undetectable to 71% of the total C6 -C3 metabolites excreted, and any benefit accruing from this metabolite will not necessarily be available to all consumers.

Psychological Stress and Functional Endometrial Disorders: Update of Mechanism Insights

The human endometrium plays a vital role in providing the site for embryo implantation and maintaining the normal development and survival of the embryo. Recent studies have shown that stress is a common factor for the development of unexplained reproductive disorders. The nonreceptive endometrium and disturbed early maternal-fetal interaction might lead to infertility including the repeated embryo implantation failure and recurrent spontaneous abortion, or late pregnancy complications, thereby affecting the quality of life as well as the psychological status of the affected individuals. Additionally, psychological stress might also adversely affect female reproductive health. In recent years, several basic and clinical studies have tried to investigate the harm caused by psychological stress to reproductive health, however, the mechanism is still unclear. Here, we review the relationship between psychological stress and endometrial dysfunction, and its consequent effects on female infertility to provide new insights for clinical therapeutic interventions in the future.

Analysis of the relationship between COMT polymorphisms and endometriosis susceptibility

This study was aimed to explore the correlation between catechol-O-methyltransferase (COMT) gene polymorphisms and endometriosis susceptibility in Chinese Han population.This case-control study recruited 134 endometriosis patients and 139 healthy individuals. COMT gene rs4680, rs2020917, and rs4646312 polymorphisms in the subjects were genotyped by the polymerase chain reaction-restriction fragment length polymorphism method. Association between COMT polymorphisms and endometriosis susceptibility was evaluated by χ test and adjusted by Logistic regression. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to present the relative risk of endometriosis.A allele of rs4680 was distinctly correlated with increased susceptibility of endometriosis (OR = 1.450, 95% CI = 1.012-2.076). However, when adjusted by the confounding factors, these associations become not significant. We failed to find any significant association between rs2020917 and endometriosis risk in the crude results. The adjusted results suggested that rs2020917 TT genotype and T allele were distinctly correlated with enhanced endometriosis risk (TT vs CC: P = .038, OR = 2.894, 95% CI = 1.060-7.903; T vs C: P = .039, OR = 1.481, 95% CI = 1.021-2.149). Besides, rs4646312 C allele was significantly correlated with endometriosis risk both in the crude (P = .027, OR = 1.502, 95% CI = 1.047-2.154) and adjusted (P = .019, OR = 1.564, 95% CI = 1.078-2.269) results.COMT polymorphisms might predict the occurrence of endometriosis.

The significance of polymorphism and expression of oestrogen metabolism-related genes in Chinese women with premature ovarian insufficiency

The aim of this study was to investigate whether polymorphism and expression of CYP17, CYP1A1, COMT and SULT1A1 affected the risk of idiopathic primary ovarian insufficiency (POI) in Chinese women. DNA sequencing and real-time PCR were used to detect these genes in 132 cases of idiopathic POI and 132 normal women. A significant increase in the C allele of CYP17 (rs743572) polymorphism was observed in women with POI compared with controls (P_FDR = 0.046). A significant decrease was observed in the C allele of CYP1A1 (rs4646903) in women with POI compared with controls (P_FDR = 0.004). The A allele of COMT (rs4680) polymorphism was more frequent in women with POI compared with controls (P_FDR = 0.029). The genotypic frequency of SULT1A1 (rs9282861) was not significantly different between the two groups. For the relative expression of CYP17 and COMT were statistically significant (both P_FDR = 0.066), with false discovery rate controlled at 0.1. No significant difference was observed in the RNA levels of CYP1A1 and SULT1A1 between the two groups. The frequency of expression of the CYP17 T/C variant tended to be higher and the A allele of COMT polymorphism together with down-regulation of its mRNA expression may be more frequent in Chinese women with idiopathic POI.

From Pregnancy to Preeclampsia: A Key Role for Estrogens

Preeclampsia (PE) results in placental dysfunction and is one of the primary causes of maternal and fetal mortality and morbidity. During pregnancy, estrogen is produced primarily in the placenta by conversion of androgen precursors originating from maternal and fetal adrenal glands. These processes lead to increased plasma estrogen concentrations compared with levels in nonpregnant women. Aberrant production of estrogens could play a key role in PE symptoms because they are exclusively produced by the placenta and they promote angiogenesis and vasodilation. Previous assessments of estrogen synthesis during PE yielded conflicting results, possibly because of the lack of specificity of the assays. However, with the introduction of reliable analytical protocols using liquid chromatography/mass spectrometry or gas chromatography/mass spectrometry, more recent studies suggest a marked decrease in estradiol levels in PE. The aim of this review is to summarize current knowledge of estrogen synthesis, regulation in the placenta, and biological effects during pregnancy and PE. Moreover, this review highlights the links among the occurrence of PE, estrogen biosynthesis, angiogenic factors, and cardiovascular risk factors. A close link between estrogen dysregulation and PE occurrence might validate estrogen levels as a biomarker but could also reveal a potential approach for prevention or cure of PE.

COMT polymorphism influences decrease of ovarian follicles and emerges as a predictive factor for premature ovarian insufficiency

Background

Estrogens are important factors in the female reproductive functions and are processed by a number of enzymes along their metabolic pathway. The COMT gene constitutes a crucial element in estrogen metabolism and is assumed to be involved in the development of Premature Ovarian Insufficiency (POI). This study aimed to determine whether the presence of the COMT Val/Met polymorphism (rs4680) is associated to the risk of developing POI.

Findings

In this case–control study, we evaluated 96 infertile women with POI and 120 fertile women as controls, after obtaining a detailed history of the disease and follicle-stimulating hormone measurements, besides karyotype determination and fragile-X premutation syndrome investigation. COMT (Val/Met) genotypes were identified by real time PCR (genotyping TaqMan assay), and the results were statistically analyzed. A statistically significant difference was found in the distribution of COMT genotypes (p = 0.003) and alleles (p = 0.015) between the POI patients and the control group.

Conclusion

We were able to demonstrate a strong association between the COMT Val/Met polymorphism and the risk of premature ovarian insufficiency in the Brazilian women evaluated. However, further studies in larger populations are necessary to confirm these findings.

Pregnancy ameliorates the inhibitory effects of 2-methoxyestradiol on angiogenesis in primary sheep uterine endothelial cells

The estrogen metabolite 2-methoxyestradiol (2-ME2) is one of the most potent antiangiogenic and proapoptotic endogenous steroids. Herein, we investigate the effects of 2-ME2 on angiogenesis of cultured primary ovine uterine artery endothelial cells (UAECs) from nonpregnant follicular (F-UAECs), nonpregnant luteal (L-UAECs), and pregnant ewes (P-UAECs). Uterine artery endothelial cells were treated with vehicle control, 10(-8) mol/L 17β-estradiol (17βE2), or 10(-9) to 10(-6) mol/L 2-ME2. Angiogenesis, apotosis, and cell morphology were assessed by capillary tube formation, flowcytometry, and immunohistochemistry. 17βE2 stimulated while 10(-6) mol/L 2-ME2 inhibited capillary tube formation in F-UAECs (P < .05). The inhibitory effects of 2-ME2 on angiogenesis were minimal in L-UAECs and were absent in P-UAECs when compared to controls. 10(-6) mol/L 2-ME2 increased apoptosis and inhibited microtubular structure equally in pregnant and nonpregnant UAECs when compared to control or 17βE2 treatments. Thus, 2-ME2 inhibit capillary tube formation in F-UAECs while L-UAECs and P-UAECs are relatively unresponsive to the inhibitory effects of 2ME2 indicating that the pregnancy phenotypic state of the UAECs may modulate the action of 2-ME2 on capillary angiogenesis.

Promoter hypomethylation of COMT in human placenta is not associated with the development of pre-eclampsia

Disruption of the Catechol-O-methyltransferase (COMT) gene has been shown to be involved in pre-eclampsia (PE). To investigate whether two promoters of the COMT gene are differentially regulated by methylation in PE patients, we have analyzed the genomic DNA extracted from placenta (cases n = 16; controls n = 21), maternal peripheral blood (cases n = 4; controls n = 6) and umbilical cord blood (cases n = 8; controls n = 8) of women with PE and women with normal pregnancy. Bisulfite sequencing identified the predominantly unmethylated MB-COMT promoter in placenta, maternal peripheral blood and umbilical cord blood samples (PE and control). Subsequent quantitative MassArray data confirmed a significant tissue-specific hypomethylation of the S-COMT promoter in placenta (mean = 28.6%) when compared with its densely methylated patterns in blood samples (mean = 74.5%, P < 0.001), consistent with the sequencing data. However, no PE-specific methylation difference was found between cases and controls either in placenta or in blood samples. Moreover, none of the clinical characteristics had an effect on the methylation status of the S-COMT promoter. This study does not support a causal link between methylation regulation of COMT promoters and PE. However, the observed placenta-specific S-COMT promoter may be a potential marker for early prediction of PE in maternal plasma, although this remains to be further evaluated.

Vitamin D inhibits proliferation of human uterine leiomyoma cells via catechol-O-methyltransferase

OBJECTIVE

To evaluate the effects and mechanisms of action of vitamin D on human uterine leiomyoma (HuLM) cell proliferation in vitro.

DESIGN

Laboratory study.

SETTING

University hospitals.

PATIENTS(S)

Not applicable.

INTERVENTIONS(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

HuLM cells were treated with 1,25-dihydroxyvitamin D3 (vitamin D), and cell proliferation was assayed by the methylthiazolyl tetrazolium technique. proliferating cell nuclear antigen (PCNA), BCL-2, BCL-w, cyclin-dependent kinase (CDK) 1, and catechol-O-methyltransferase (COMT) protein levels were analyzed by Western blotting. COMT mRNA and enzyme activity were assayed by quantitative reverse-transcription polymerase chain reaction (RT-PCR) and high-performance liquid chromatography analysis, respectively. The role of COMT was evaluated in stable HuLM cells by silencing COMT expression.

RESULT(S)

Vitamin D inhibited the growth of HuLM cells by 47±0.03% at 1 μM and by 38±0.02% at 0.1 μM compared with control cells at 120 hours of treatment. Vitamin D inhibited extracellular signal-regulated kinase activation and down-regulated the expression of BCL-2, BCL-w, CDK1, and PCNA. Western blot, RT-PCR, and enzyme assay of COMT demonstrated inhibitory effects of vitamin D on COMT expression and enzyme activity. Silencing endogenous COMT expression abolished vitamin D-mediated inhibition of HuLM cell proliferation.

CONCLUSION(S)

Vitamin D inhibits growth of HuLM cells through the down-regulation of PCNA, CDK1, and BCL-2 and suppresses COMT expression and activity in HuLM cells. Thus, hypovitaminosis D appears to be a risk factor for uterine fibroids.

Recent advances on the action of estrogens and progestogens in normal and pathological human endometrium

Hormonal control in the development of the normal endometrium is of the utmost importance. It is well established that the two main hormones involved in this process are estradiol and progesterone, which are also implicated in the pathological conditions concerning endometriosis and endometrial carcinoma. There are two types of endometrial carcinoma: type I which represents 80%–90% is hormone-dependent, whereas the remainder is type II and is hormone-independent. The endometrial tissue contains all the enzymatic systems in the formation and transformation of the various hormones, including aromatases, sulfatases, sulfotransferases, hydroxysteroid dehydrogenases, hydroxylases, and glucuronidases. It is interesting to note that increased sulfatase activity is correlated with severity of endometriosis. An increased sulfatase/sulfotransferase ratio represents a poor prognosis in patients with endometrial carcinoma. Treatment with hormone replacement therapy (estrogens+progestogens), as well as with tibolone, is most effective in protecting this tissue by climacteric alterations, owing to the significant decrease of ovarian hormones. In conclusion, enzymatic control can open appealing perspectives to protect this organ from possible pathological alterations.

Elevated expression of catechol-O-methyltransferase is associated with labor and increased prostaglandin E(2) production by human fetal membranes

OBJECTIVE

The purpose of this study was to evaluate the expression and function of catechol-O-methyltransferase in human fetal membranes at term.

STUDY DESIGN

Fetal membranes obtained from women between 38-42 weeks of gestation, after (1) vaginal delivery with spontaneous labor and (2) prelabor elective cesarean section (no labor), were assayed for catechol-O-methyltransferase expression using quantitative real-time polymerase chain reaction analysis, immunohistochemistry, and Western blot analysis. Prostaglandin E(2) secretion from amnion and choriodecidua explants treated with or without catechol-O-methyltransferase inhibitor was assayed by enzyme-linked immunosorbent analysis.

RESULTS

Amnion layer of fetal membranes from laboring women expressed significantly higher levels of catechol-O-methyltransferase, compared with those from women with no labor. Catechol-O-methyltransferase was higher in the amnion layer than in choriodecidua. Selective catechol-O-methyltransferase inhibition significantly decreased prostaglandin E(2) production from fetal membranes.

CONCLUSION

Labor increases catechol-O-methyltransferase expression in the amnion of human fetal membranes. Selective catechol-O-methyltransferase inhibition decreased prostaglandin E(2) secretion in fetal explant cultures, suggesting a role for catechol-O-methyltransferase in human labor and delivery.

Increased production of 17beta-estradiol in endometriosis lesions is the result of impaired metabolism

CONTEXT

substantial evidence suggests that the expression of steroid metabolizing enzymes in endometriosis is altered, turning the ectopic endometrium into a source of 17beta-estradiol. However, whether these differences result in a net increase in local 17beta-estradiol production/activity has not been shown.

SUBJECTS AND METHODS

The activities of the most important steroidogenic enzymes synthesizing and inactivating 17beta-estradiol were determined by HPLC in matched eutopic and ectopic tissue from patients with endometriosis (n = 14) and in endometrium from controls (n = 20).

RESULTS

Aromatase activity is negligible in the ectopic endometrium, whereas the activity of estrogen sulfatase is high though not different between ectopic, eutopic and control endometrium. The activity of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) converting estrone into 17beta-estradiol is higher in the ectopic compared to the eutopic endometrium in patients. The activity of 17beta-HSDs converting 17beta-estradiol back to estrone is significantly lower in the ectopic compared to the eutopic endometrium of both patients and controls. To evaluate the net metabolic capacity of tissues to synthesize 17beta-estradiol, we calculated the activity ratio between 17beta-HSDs synthesizing versus 17beta-HSDs inactivating 17beta-estradiol. This ratio is significantly higher in the ectopic compared to the eutopic endometrium of patients and controls, indicating a high synthesis of 17beta-estradiol in the ectopic locations. This is further supported by the elevated mRNA levels of the estrogen-responsive gene TFF1 in all ectopic compared to eutopic endometria.

CONCLUSION

Endometriotic lesions have higher production of 17beta-estradiol than the eutopic endometrium of patients and controls. This is mostly the result of impaired metabolism.