Associations between estrogen receptor-beta polymorphisms and endometriosis risk: a meta-analysis

Estrogen and progesterone receptors in endometriosis

BACKGROUND

This study aims to identify the presence of estrogen and progesterone hormone receptors in endometriosis implants and to determine whether hormone treatment influences the receptors in these implants.

METHODS

Cross-sectional study with historical data collection. The analysis was conducted on 156 endometriosis implants from 67 patients undergoing endometriosis laparoscopy. The patients were divided into two groups: one group underwent hormone treatment (n = 20) and another group did not receive hormone treatment (n = 47) prior to surgery. Women of reproductive age with clinical pain and/or infertility who were diagnosed with endometriosis and underwent surgery were included. The specimens were analyzed after the estrogen and progesterone hormone receptors underwent immunohistochemistry.

RESULTS

All analyzed topographies presented estrogen and progesterone hormone receptors. Progesterone hormone receptor expression was considerably superior than estrogen receptor expression (p < 0.001).

CONCLUSIONS

Hormone receptors are present in endometriosis implants on the ovarian fossae, uterosacral ligaments, sac fundus, and ovaries. Progesterone receptors predominate in implants, regardless of hormonal treatment.

Investigating the rate of different ovarian response in in vitro fertilization cycles based on estrogen receptor beta +1730 polymorphism: A cross-sectional study

Background

The response to ovarian stimulation is different among women referring for assisted reproductive techniques. This difference could be due to different genotypes in genes related to reproduction such as estrogen receptor beta (ERβ or ESR2) gene.

Objective

In the present study, we explored the rate of ESR2 gene polymorphism in infertile women undergoing IVF treatment with different ovarian response to ovulation induction.

Materials and Methods

A cross-sectional study was performed among 91 infertile women. The relationship between genotype distribution of the +1730 G/A polymorphism in the ESR2 gene (rs4986938) and the mean number of follicles and oocytes, their mean ratio, mean number of embryos, mean size of the follicles and pregnancy rates were measured. The ESR2 gene +1730 G/A polymorphism were identified by the amplification-refractory mutation system-polymerase chain reaction.

Results

Genotypes GG, GA, and AA of the ESR2 gene presented frequencies of 27.5%, 67%, and 5.5%, respectively, in the infertile women. The results of the study showed that the mean number of follicles and oocytes, their mean ratio, mean number of embryos, mean size of the follicles, and pregnancy rates are not related to different genotypes.

Conclusion

According to the endocrine and paracrine factors which are involved in the ovulation induction and maturation of oocytes, more studies with higher number of participants are required to confirm the results of the present study; in addition, further studies are required to find out other gene polymorphisms affecting estrogen receptor efficacy in the infertile women.

Epigenetics of Estrogen and Progesterone Receptors in Endometriosis

Endometriosis is an estrogen-dependent inflammatory gynecological disease. Increased estrogen activity and progesterone resistance are the main hormonal substrate of this disease and are associated with inflammatory response and debilitating symptoms, including pain and infertility. Estrogens and progesterone act via their specific nuclear receptors. The regulation of receptor expression by epigenetics maybe a critical factor for endometriosis. The present review aims to discuss the epigenetic mechanisms related to the expression of estrogen receptors (ERs) and progesterone receptors (PRs) in patients with endometriosis, including two classic epigenetic mechanisms: DNA methylation and histone modification, and, other non-classic mechanisms: miRNAs and lncRNA. Several in vitro and in vivo studies support the key role of epigenetics in the regulation of the expression of ERs and PRs, which may provide new molecules and targets for the diagnosis and treatment of endometriosis.

Endometriosis and nuclear receptors

BACKGROUND

Endometriosis is recognized as a steroid-dependent disorder; however, the precise roles of nuclear receptors (NRs) in steroid responsiveness and other signaling pathways are not well understood.

OBJECTIVE AND RATIONALE

Over the past several years, a number of paradigm-shifting breakthroughs have occurred in the area of NRs in endometriosis. We review and clarify new information regarding the mechanisms responsible for: (i) excessive estrogen biosynthesis, (ii) estrogen-dependent inflammation, (iii) defective differentiation due to progesterone resistance and (iv) enhanced survival due to deficient retinoid production and action in endometriosis. We emphasize the roles of the relevant NRs critical for these pathological processes in endometriosis.

SEARCH METHODS

We conducted a comprehensive search using PubMed for human, animal and cellular studies published until 2018 in the following areas: endometriosis; the steroid and orphan NRs, estrogen receptors alpha (ESR1) and beta (ESR2), progesterone receptor (PGR), steroidogenic factor-1 (NR5A1) and chicken ovalbumin upstream promoter-transcription factor II (NR2F2); and retinoids.

OUTCOMES

Four distinct abnormalities in the intracavitary endometrium and extra-uterine endometriotic tissue underlie endometriosis progression: dysregulated differentiation of endometrial mesenchymal cells, abnormal epigenetic marks, inflammation activated by excess estrogen and the development of progesterone resistance. Endometriotic stromal cells compose the bulk of the lesions and demonstrate widespread epigenetic abnormalities. Endometriotic stromal cells also display a wide range of abnormal NR expression. The orphan NRs NR5A1 and NR2F2 compete to regulate steroid-synthesizing genes in endometriotic stromal cells; NR5A1 dominance gives rise to excessive estrogen formation. Endometriotic stromal cells show an abnormally low ESR1:ESR2 ratio due to excessive levels of ESR2, which mediates an estrogen-driven inflammatory process and prostaglandin formation. These cells are also deficient in PGR, leading to progesterone resistance and defective retinoid synthesis. The pattern of NR expression, involving low ESR1 and PGR and high ESR2, is reminiscent of uterine leiomyoma stem cells. This led us to speculate that endometriotic stromal cells may display stem cell characteristics found in other uterine tissues. The biologic consequences of these abnormalities in endometriotic tissue include intense inflammation, defective differentiation and enhanced survival.

WIDER IMPLICATIONS

Steroid- and other NR-related abnormalities exert genome-wide biologic effects via interaction with defective epigenetic programming and enhance inflammation in endometriotic stromal cells. New synthetic ligands, targeting PGR, retinoic acid receptors and ESR2, may offer novel treatment options.

Polymorphisms in the 3'UTR Region of ESR2 and CYP19A1 Genes in Women With Endometriosis

OBJECTIVE

ESR2 and CYP19A1 genes play a major role in the hormonal control of women with endometriosis. The aim of the study was to analyze single nucleotide polymorphisms (SNPs) in the 3'UTR region of ESR2 and CYP19A1 genes. The study aimed at localisation of new polymorphisms, the nucleotide variants of which determine the level of susceptibility to endometriosis.

STUDY DESIGN

The study included n = 200 patients: 100 with endometriosis and 100 healthy controls. The Sanger's sequencing method was applied for polymorphism analysis.

RESULTS

Statistically significant correlations were identified between new, not previously described, two SNPs of ESR2 gene and endometriosis: rs4986938 (G>A) and rs928554 (A>G). In the case of rs4986938 polymorphism, the genotype AA was found to decrease the risk of endometriosis (OR = 0.24 95 % PU 0.05-1.22, p = 0.04). Analysis of the rs928554 polymorphism revealed that the occurrence of the AG genotype reduced the risk of endometriosis (OR = 0.38 95 % PU 0.21-0.71, p = 0.002). There were no differences in the distribution of genotypes of the polymorphisms rs10046 (C>T) and rs4646 (C>A) of CYP19A1 gene between patients and control.

CONCLUSIONS

Further studies are necessary in groups with higher numbers of patients to explain whether the above-mentioned polymorphisms may be the risk factors for endometriosis.

Association of genetic polymorphisms of estrogen and progesterone receptors and endometriosis: Meta-analysis

Purpose:

To investigate the association between polymorphisms in the genes of estrogen receptor alpha, estrogen receptor beta, and progesterone receptor and the genesis of endometriosis.

Methods:

Systematic review and meta-analysis of articles published fully in the PubMed database, in Portuguese, English, or Spanish, from 2006 to 2017, using the descriptors: “endometriosis,” “polymorphism,” “ESR1,” “ESR2,” “PROGINS,” “rs9340799,” “rs4986938,” and “rs1042838.”

Results:

A total of 20 studies were included based on the criterion of search for susceptibility to endometriosis related to polymorphisms of estrogen receptor alpha, estrogen receptor beta, and progesterone receptor genes. Analysis of all polymorphisms found no association with endometriosis.

Conclusion:

This meta-analysis showed that estrogen receptor alpha, estrogen receptor beta, and progesterone receptor polymorphisms are not related to susceptibility to endometriosis. However, such results may be able to provide more detailed interpretations of how they influence the pathogenesis of endometriosis.

A review of the risk factors, genetics and treatment of endometriosis in Chinese women: a comparative update

Endometriosis is one of the major causes of economic burden and compromised quality of life in a very large percentage of Asian women. While it is perceived as a benign condition, recent research has shown that it may be a significant cause of infertility and metastatic cancer. It has also been associated with other diseases linked to the functioning of the immune system. Genetic as well as environmental factors are known to affect the manifestation and progression of endometriosis. This review aims to summarize recent research pertaining to the risk factors, diagnosis and treatment of endometriosis in Chinese women. It also provides an overview of identified genetic mutations and polymorphisms and their effects on the risk of developing endometriosis in the Chinese population. A comparison has been drawn between Asian and European-American female populations and the differences in risk factors and treatment responses have been summarized. Since traditional Chinese medicine (TCM) is often used to treat endometriosis, wherever possible, a comparison between efficacies of Western medicine and TCM in the Chinese population has also been provided. Although much progress has been made in the treatment and resolution of endometriosis, several gaps remain and this review also highlights possible areas of future research and advancement that can result in an improvement in patient outcomes and quality of life.