Estrogen receptor 2 and progesterone receptor gene polymorphisms and lipid levels in women with different hormonal status

Is the beta estradiol receptor receiving enough attention for its metabolic importance in postmenopause?

The relationship between menopause and the development of metabolic diseases is well established. In postmenopause women, there is an expansion of visceral white adipose tissue (WATv), which highly contributes to the rise of circulating lipids. Meanwhile, muscle glucose uptake decreases and hepatic glucose production increases. Consequently, in the pancreas, lipotoxicity and glycotoxicity lead to deficient insulin production. These factors initiate an energy imbalance and enhance the probability of developing cardiovascular and metabolic diseases. Although the activation of estradiol receptors (ER) has been shown to be beneficial for the WAT stock pattern, leading to the insulin-sensitive phenotype, authors have described the risk of these receptors' activation, contributing to neoplasia development. The selective activation of beta-type ER (ERβ) seems to be a promising strategy in the treatment of energy imbalance, acting on several tissues of metabolic importance and allowing an intervention with less risk for the development of estrogen-dependent neoplasia. However, the literature on the risks and benefits of selective ERβ activation still needs to increase. In this review, several aspects related to ERβ were considered, such as its physiological role in tissues of energy importance, beneficial effects, and risks of its stimulation during menopause. PubMed, SciELO, Cochrane, and Medline/Bireme databases were used in this study.

ESR2 gene G1730A variant is associated with triglycerides level and myocardial infarction in young men but not in women

OBJECTIVES

The aim of the study was to investigate the role of estrogen receptor type 2 gene (ESR2) variant G1730A in myocardial infarction (MI) in young age.

METHODS

Genotyping was performed with restriction fragments length polymorphism method in 158 patients (79.1% men) with MI aged <50 years (studied group) and in control groups: 150 healthy individuals aged <50 years (63.3% men) and 202 patients (64.3% men) with MI aged ≥50 years.

RESULTS

The AA genotype of ESR2 G1730A variant was significantly more frequent in men with MI aged <50 comparing to men with MI aged ≥50 (21.6% vs. 8.4%, P = 0.004) and to healthy young men (21.6% vs. 11.6%, P = 0.048). There was statistically significant difference between AA genotype and GA + GG genotypes male carriers with MI aged <50 in median triglyceride (TG) level (2.0 vs. 1.7 mmol/l respectively, p = 0.023).

CONCLUSIONS

Our findings suggest a possible role of ESR2 G1730A variant as the risk factor of MI in a young age not as an independent but a potential risk factor associated with TG level in men but not in women.

Associations of estrogen receptor alpha and Beta gene polymorphisms with lipid levels and insulin resistance in men

OBJECTIVE

The association of four single nucleotide polymorphisms in estrogen receptor alpha (ESR1) and beta (ESR2) genes with lipid levels and insulin resistance in men.

DESIGN AND METHODS

Lipids, glucose, insulin and HOMA-IR were determined, in a population-based, cross-sectional, cohort of 170 apparently healthy middle-aged Greek men, along with body mass index (BMI), waist circumference (WC) and percentage of body fat content (%fat). Genotyping of ESR1 for PvuII and XbaI and ESR2 for RsaI and AluI polymorphisms was performed.

RESULTS

Associations of AluI with LDL-Chol (mean ± SD, aa 4.3 ± 1.1 vs. Aa 3.7 ± 1.0 and ΑΑ 4.2 ± 1.1, p = 0.023) and RsaI with HOMA-IR [median (IQR), RR 1.55 (0.88-2.49) vs. Rr/rr 1.69 (0.72-2.29), p = 0.032] were found. Synergistic effects of RsaI and AluI of ESR2 gene on LDL-Chol levels, %fat and WC, as well as a synergistic effect of both ESR1 and ESR2 genes on levels of TChol (p = 0.01) and LDL-Chol (p = 0.027) were also shown. These findings remained significant after adjustment for potential confounders. Significant independent associations of PvuII with %fat (mean ± SD, pp 24.6 ± 5.3 vs Pp 22.4 ± 5.2 and PP 21.2 ± 6.7, p = 0.044), and RsaI with %fat (RR 22.6 ± 5.5 vs. Rr/rr 25.2 ± 6.3, p = 0.015) and WC (mean ± SD, RR 97.4 ± 10.4 vs. Rr/rr 102.6 ± 12.6, p = 0.013) were found. Synergistic effects on %fat, between the ESR1 polymorphisms (p = 0.004), between the ESR2 polymorphisms and among all four ESR polymorphisms studied were also present.

CONCLUSIONS

ESR2 is associated with LDL-Chol levels and HOMA-IR in men independently of confounders. Body fat is affected by both genes. Furthermore, a synergistic effect of ESR1 and ESR2 on TChol, LDL-Chol and %fat, was shown.

Are polymorphisms in oestrogen receptors genes associated with lipid levels in response to hormone therapy?

BACKGROUND

Polymorphisms in the oestrogen receptor 1 (ESR1) and oestrogen receptor 2 (ESR2) genes are associated with intermediate or endpoint markers of cardiovascular disease and with the efficacy of postmenopausal hormone therapy (HT). Contradictory findings have been described in the past and the role of these genetics variants remains unclear.

METHODS

A cross-sectional study was carried out with 266 postmenopausal women, of whom 115 received oral HT (HT+) and 151 did not receive any HT (HT-). We analysed three single-nucleotide polymorphisms (SNPs) in ESR1 (rs1801132, rs7757956 and rs2813544) and two in ESR2 (rs3020450 and rs7154455) and derived haplotypes with three additional polymorphisms that had been previously investigated by our group (ESR1 rs2234693 and ESR2 rs1256049 and rs4986938).

RESULTS

The ESR1 rs2813544 polymorphism was associated with low-density lipoprotein cholesterol (LDL-C) in HT+ postmenopausal women (p = 0.044; pC = 0.388), while one ESR2 gene haplotype was associated with total cholesterol (T-chol) (p = 0.015; pC = 0.090) and LDL-C in HT+ postmenopausal women (p = 0.021; pC = 0.126).

CONCLUSION

Our findings suggest that, in HT+ postmenopausal women, the rs2813544 polymorphism may influence LDL-C levels and, as previously described, ESR2 rs1256049 is associated with T-chol and LDL-C. No previous study has investigated the association of this SNP set with lipoprotein levels in women while taking into account the hormonal status of the patients.

Association of estrogen receptor β gene polymorphisms with vascular dementia in women

The objective of the present study was to explore a potential association between the estrogen receptor β (ERβ) gene polymorphisms and vascular dementia (VaD) in women. The relationship of two polymorphisms (rs944050 and rs4986938) and their associated haplotypes in the ERβ gene with VaD were examined in 121 Chinese Han women (>50 years of age) including 61 with VaD and 60 healthy age-matched controls. The potential associations were evaluated using unconditional logistic regression. The variant allele G of rs944050 in the ERβ gene increased the risk of VaD (odds ratio = 2.02, 95% confidence interval = 1.08-3.77). In haplotype analyses, the ERβ haplotype containing the polymorphism rs944050 variant allele and the polymorphism rs4986938 wild-type allele was associated with VaD (odds ratio = 1.70, 95% confidence interval = 1.03-2.84). The polymorphism rs944050 in the ERβ gene was associated with an increased risk of VaD in Chinese Han women. Further studies regarding the association between the ERβ gene polymorphisms and VaD are needed to confirm these findings.

Evaluation of UGT1A1 and SULT1A1 polymorphisms with lipid levels in women with different hormonal status

BACKGROUND

Estrogens influence many physiological processes including cardiovascular health. Polymorphisms in phase I and II estrogen metabolism enzymes are associated with lipid levels in women.

METHODS

A cross-sectional study was carried out with 269 postmenopausal women, 116 who received oral hormonal therapy (HT) (39-75 years) with estrogens or estrogens plus progestagen, 153 that did not receive any HT (38-85 years), and 155 premenopausal women (18-52 years). Polymorphisms in UGT1A1 (rs5839491) and SULT1A1 (rs1042028) were analysed by PCR-based methods. Adjusted lipid levels means were compared among genotypes by one-way analysis of variance, with corrections for multiple testing.

RESULTS

The UGT1A1*28 polymorphism was associated with total cholesterol (T-chol) (p = 0.030; corrected p = 0.060) and low-density lipoprotein cholesterol (LDL-C) levels (p = 0.011, corrected p = 0.022) in premenopausal women. The premenopausal and postmenopausal women, both carriers of SULT1A1*2/*2, had lower levels of T-chol and LDL-C means than carriers of the SULT1A1*1/*1 (p = 0.004, corrected p = 0.008 and 0.009, corrected p = 0.018, respectively).

CONCLUSION

The data showed the presence of an association between the UGT1A1*28/*28 and SULT1A1*2/*2 and T-chol and LDL-C levels in women with different hormonal status. No previous studies investigated the association of the polymorphisms examined in this study with lipoprotein levels in women separately by hormonal status.

Associations of the estrogen receptors 1 and 2 gene polymorphisms with the metabolic syndrome in women

BACKGROUND

Genetic variation of the estrogen receptor alpha (ESR1) and beta (ESR2) has been associated with components of the metabolic syndrome.

METHODS

The relationships of two ESR1 (rs2234693 and rs9340799) and three ESR2 (rs1271572, rs1256049, and rs4986938) polymorphisms with the metabolic syndrome were examined in 532 Caucasian female participants (median age 63.1 years) in the Women's Health Study. Most women (99.1%) were postmenopausal. The associations between ESR1 and ESR2 genotypes and haplotypes with the metabolic syndrome were evaluated. Effect modification by hormone therapy was also assessed.

RESULTS

Genotype and haplotype distributions were similar between women with and without metabolic syndrome. We found no consistent associations between the genotypes and haplotypes tested and the metabolic syndrome, or its components, in logistic regression models. No effect modification by hormone therapy use was noted.

CONCLUSIONS

No association between these genetic variants in ESR1 and ESR2 and the metabolic syndrome was observed among these Caucasian women. Further investigation regarding the potential involvement of estrogen receptor genes and the metabolic syndrome may be warranted in other ethnic groups.

Gene polymorphisms that may influence the biological effects of progestins

Many of the biological actions of progestins depend on binding to intracellular receptors and through a long chain of events to subsequent stimulation of transcriptional activity and protein synthesis. This process requires at least a few hours in time and many different proteins called coregulators do play a role after binding to the receptor. Evidence for polymorphisms in the gene coding for the PR has been obtained and many studies have already attempted to show associations between particular polymorphisms and human diseases. However, at present no consistent and conclusive picture has emerged on clinically important associations. Studies on links between polymorphisms in genes coding for coregulators are just beginning. The second pathway, the so-called non-genomic actions, is related to rapid effects of progestins that occur within minutes. At this moment a number of different membrane bound receptors have been identified. No data are available yet on polymorphisms in genes coding for these proteins or to link any of these membrane receptors to specific human pathology.

Do Estrogen Receptor beta Polymorphisms Play A Role in the Pharmacogenetics of Estrogen Signaling?

Estrogen hormones play critical roles in the regulation of many tissue functions. The effects of estrogens are primarily mediated by the estrogen receptors (ER) alpha and beta. ERs are ligand-activated transcription factors that regulate a complex array of genomic events that orchestrate cellular growth, differentiation and death. Although many factors contribute to their etiology, estrogens are thought to be the primary agents for the development and/or progression of target tissue malignancies. Many of the current modalities for the treatment of estrogen target tissue malignancies are based on agents with diverse pharmacology that alter or prevent ER functions by acting as estrogen competitors. Although these compounds have been successfully used in clinical settings, the efficacy of treatment shows variability. An increasing body of evidence implicates ERalpha polymorphisms as one of the contributory factors for differential responses to estrogen competitors. This review aims to highlight the recent findings on polymorphisms of the lately identified ERbeta in order to provide a functional perspective with potential pharmacogenomic implications.

Gender-specific effect of estrogen receptor-1 gene polymorphisms in coronary artery disease and its angiographic severity in Chinese population

BACKGROUND

The role of common polymorphisms of the estrogen receptor-1 in coronary artery disease (CAD) and it association with angiographic severity reminds conflicting in sexes and different races.

METHODS

Two-hundred ten angiographically defined Chinese CAD patients and 174 control subjects were enrolled. DNA was obtained and the polymorphisms were analyzed by the polymerase chain reaction. The region containing the PvuII T/C and the XbaI A/G sites was amplified. PCR product was cleaved with the restriction endonucleases.

RESULTS

No significant differences in PvuII and XbaI genotype and allele frequencies were noted between the CAD and controls.However, when stratified by gender, we noticed the PvuII genotype and allele frequencies were significantly different between CAD and controls, but in male group only, not in female group. Diabetes, hypertension, high LDL levels and the PvuII CC genotype were independent risk factors for CAD. PvuII CC was associated with the angiographic severity of CAD measuring by the number of diseased vessels as well. For XbaI, no association was found with the CAD susceptibility before and after gender stratification.

CONCLUSION

This study revealed a gender-specific effect of PvuII polymorphism in Chinese CAD subjects. PvuII gene polymorphisms affect CAD susceptibility in man only. The PvuII CC is a risk factor for CAD and it is associated with angiographic CAD severity.

Estrogen receptor genotypes, menopausal status, and the lipid effects of tamoxifen

Tamoxifen induces important changes in serum lipid profiles in some women; however, little information is available to predict which women will experience improved lipid profiles during tamoxifen therapy. As part of a multicenter prospective observational trial in 176 breast cancer patients, we tested the hypothesis that tamoxifen-induced lipid changes were associated with genetic variants in candidate target genes (CYP2D6, ESR1, and ESR2). Tamoxifen lowered low-density lipoprotein cholesterol (P<0.0001) by 23.5 mg/dl (13.5-33.5 mg/dl) and increased triglycerides (P=0.006). In postmenopausal women, the ESR1-XbaI and ESR2-02 genotypes were associated with tamoxifen-induced changes in total cholesterol (P=0.03; GG vs GA/AA) and triglycerides (P=0.01; gene-dose effect), respectively. In premenopausal women, the ESR1-XbaI genotypes were associated with tamoxifen-induced changes in triglycerides (P=0.002; gene-dose effect) and high-density lipoprotein (P=0.004; gene-dose effect). Our results suggest that estrogen receptor genotyping may be useful in predicting which women would benefit more from tamoxifen.

Polymorphisms and haplotypes of the estrogen receptor-beta gene (ESR2) and cardiovascular disease in men and women

BACKGROUND

Cohort studies suggest an association between variation in the estrogen receptor-alpha gene (ESR1) and cardiovascular disease (CVD), but data are lacking for the effect of variation in the estrogen receptor-beta gene (ESR2).

METHODS

Three polymorphisms of the ESR2 gene, and their associated haplotypes, were evaluated in 296 white women from the Women's Health Study and 566 white men from the Physicians' Health Study who developed CVD [myocardial infarction (MI) or ischemic stroke], each matched 1:1 to a member of the cohort study who remained free from CVD. Blood samples and cardiovascular risk information were collected at baseline.

RESULTS

Women, but not men, who developed CVD or MI, but not ischemic stroke, were more likely to have the rs1271572 polymorphism variant T allele (P = 0.05 and 0.02) and less likely to have the rs1256049 polymorphism variant A allele (P = 0.003 and 0.004). No associations were observed for rs4986938. In conditional logistic multivariate regression, the rs1271572 variant was associated with increased odds of CVD [odds ratio (OR) = 1.49, 95% CI: 1.10-2.01] and MI (OR = 1.46, 95% CI: 0.96-2.23), whereas the rs1256049 variant was associated with decreased odds of CVD (OR = 0.37, 95% CI: 0.17-0.79) and MI (OR = 0.25, 95% CI: 0.09-0.73) in women. A common haplotype that included the rs1271572 variant was associated with a 7-fold increased risk of MI in women.

CONCLUSIONS

Two tightly linked polymorphisms of ESR2 were associated with risk of CVD, particularly MI, in women but not men. Additional studies of ESR2 genetic variation and risk of CVD are warranted.

Hormone therapy in perimenopausal and postmenopausal women: examining the evidence on cardiovascular disease risks

Women may live for 30 years or longer after menopause with cardiovascular disease as their highest mortality risk. Menopause may correspond to health alterations for women, yet the use of estrogen during and after this transition has been controversial for the past four decades. The evidence from recent scientific studies does not support the use of hormone therapy for the prevention or treatment of cardiovascular disease, which has resulted in its removal from national guideline recommendations. However, because of concerns related to specific aspects of the research, there are gaps in the evidence. Studies are under way to evaluate alternate methods for hormone delivery, low-dose hormone therapy, and selective estrogen receptor modulators (SERMs) in reducing cardiovascular risks in perimenopausal and postmenopausal women. Implications for clinical nursing practice include education as well as assessment and counseling related to individual risk factors.

Cardiovascular risk in women: the impact of hormone replacement therapy and prospects for new therapeutic approaches

Cardiovascular disease (CVD) is the main cause of death in women. Observational studies of hormone replacement therapy (HT) and data from women with premature ovarian failure have provided support for the principle that estrogen confers protection against the development of CVD in premenopausal women. However, randomised, controlled trials investigating HT in postmenopausal women have failed to demonstrate a benefit of HT in the primary or secondary prevention of CVD. Nevertheless, HT may be effective if targeted at younger perimenopausal women. Research aimed at investigation of the cellular mechanisms of estrogen may result in the discovery of new therapeutic targets that may be able to harness the potential beneficial effects of estrogens in the cardiovascular system. An improved understanding of the distinct processes in the clinical presentation and progress of CVD in women will help develop new targets and enhance the use of current established drugs.

Sex steroid hormone polymorphisms, high-density lipoprotein cholesterol, and apolipoprotein A-1 from the Study of Women's Health Across the Nation (SWAN)

We evaluated potential associations between single nucleotide polymorphism (SNP) variants in estrogen receptor (ERalpha and ERbeta) genes, high-density lipoprotein (HDL) cholesterol, and apolipoprotein A-1 (apoA-1) concentrations in women of 4 races/ethnicities. Participants included 1,520 African American, Caucasian, Chinese, and Japanese women from the Study of Women's Health Across the Nation (SWAN) who were premenopausal or perimenopausal and who were also enrolled in the SWAN Genetics Study, which collected blood for lipid analyses and carried out lymphocyte transformation from which DNA was extracted and genotyped. We evaluated SNPs from ERalpha and ERbeta genes (ESR1 and ESR2, respectively), including ESR1 rs9340799, ESR1 rs2234693, ESR1 rs728524, ESR1 rs3798577, ESR2 rs1255998, ESR2 rs1256065, and ESR2 rs1256030. The mean HDL cholesterol and apoA-1 values for these women were 1.47 mmol/L and 1.51 g/L, respectively. Japanese women with the ESR1 rs3798577 TC genotype had significantly lower apoA-1 (P=0.02) and HDL cholesterol levels (P=0.03) than did those with the TT genotype. African American women with the ESR1 rs728524 GG genotype had higher HDL cholesterol levels than did women with the AA or AG genotypes (P=0.05). ESR2 rs1256030 and ESR2 rs1256065 genotypes were associated with HDL cholesterol concentrations in Chinese women (P=0.05). Although associations were identified between the ESR1 and ESR2 SNP variants and lipids in these women, these associations were not consistently observed across the 4 racial/ethnic groups, nor were the associations consistently inclusive of both HDL cholesterol and apoA-1. These genetic variants provide limited evidence of associations with lipids that may help explain the cardioprotective effect of premenopausal status in women.

Sex steroid hormone pathway genes and health-related measures in women of 4 races/ethnicities: the Study of Women's Health Across the Nation (SWAN)

We synthesized findings relating health outcomes and genetic variants of the sex steroid hormone pathway in women from the Study of Women's Health Across the Nation (SWAN) Genetics Study. The SWAN Genetics Study, a component of the longitudinal SWAN study, describes selected genetics characteristics of health-related attributes during the menopausal transition in African American, Caucasian, Chinese, and Japanese women. At baseline, SWAN recruited menstruating women aged 42 to 52 years, who were not using exogenous hormones. Immortalized cell lines were developed and genotyped in 1,538 specimens from 1,757 participants in the genetics study. Genotypes and haplotypes from 6 genes (27 single nucleotide polymorphisms [SNPs]) in the sex steroid hormone pathway were related to circulating hormone concentrations, menstrual cycle profiles, and health-related outcomes, including lipids, diabetes mellitus, depressive symptoms, measures of cognition, bone mineral density (BMD), and vasomotor symptoms. Allele frequencies and distances differed substantially in the 4 race/ethnicity-specific groups evaluated, leading to variable patterns of association with health-related measures. For example, 17HSD genotypes were highly associated with diabetes risk in Caucasian women, whereas its haplotypes were associated with diabetes risk in both African American and Caucasian women. Several SNPs were associated with multiple outcomes. ESR1 rs3798577 was significantly associated with circulating estradiol concentrations, indicators of ovarian aging, high-density lipoprotein (HDL) cholesterol, apolipoprotein A-1, insulin sensitivity, and lumbar spine BMD. CYP1A1 rs2606345 was related to estrogen metabolite concentrations, vasomotor symptoms, and depressive symptoms. Some associations were much more prominent in specific races/ethnicities; Chinese women had statistically significant relations between ESR2 rs1256030 and HDL cholesterol, lumbar spine BMD, hip BMD, and metabolic syndrome. Importantly, women in the SWAN Genetics Study were typical of women in the community-based SWAN sample. This community-based sample of women from the SWAN Genetics Study identified important genetic sex steroid hormone pathway variants in relation to measures of health status. The magnitude and breadth of these relationships should motivate further research to verify and extend the findings.

Characterizing variation in sex steroid hormone pathway genes in women of 4 races/ethnicities: the Study of Women's Health Across the Nation (SWAN)

This report characterizes genotypes and haplotypes in 6 genes (27 single nucleotide polymorphisms [SNPs]) from the Sex Steroid Hormone Genetics Protocol developed though the DNA Repository of the Study of Women's Health Across the Nation (SWAN) Genetics Study. The SWAN Genetics Study is a component of a longitudinal study describing health-related attributes of the menopausal transition in African American, Caucasian, Chinese, Hispanic, and Japanese women. At baseline, SWAN recruited menstruating women, aged 42 to 52 years, who were not using exogenous hormones. During the sixth and seventh years of the study, buccal cells in a mouthwash slurry and whole blood were collected for a DNA repository. Immortalized cell lines were created and genotyped in 1,538 specimens from 1,757 women who participated in the SWAN Genetics Study. DNA from those cells was genotyped for genes in the sex steroid hormone pathway. SNPs were evaluated for genotype and allele frequencies (and differences) according to race/ethnicity and haplotyped in anticipation of studying their associations with health-related measures. We demonstrated that allele frequencies differed significantly by race/ethnicity. There was substantial linkage disequilibrium among many of the SNPs and only a few SNPs showed significant Hardy-Weinberg disequilibrium within race/ethnicity. Finally, there are a number of haplotype patterns that vary according to race/ethnicity, including a "yin-yang" pattern for 17HSD among Caucasian, Chinese, and Japanese women, but not among African American women. Repository specimens developed in anticipation of genomic or metabolomics studies can extend the contribution of the parent study by developing hybrid strategies that support both SNP association studies as well as coarse and fine mapping to evaluate possible genomic locations of causal variants.

Structure-function relationship of estrogen receptor alpha and beta: impact on human health

17Beta-estradiol (E2) controls many aspects of human physiology, including development, reproduction and homeostasis, through regulation of the transcriptional activity of its cognate receptors (ERs). The crystal structures of ERs with agonists and antagonists and the use of transgenic animals have revealed much about how hormone binding influences ER conformation(s) and how this conformation(s), in turn, influences the interaction of ERs with co-activators or co-repressors and hence determines ER binding to DNA and cellular outcomes. This information has helped to shed light on the connection between E2 and the development or progression of numerous diseases. Current therapeutic strategy in the treatment of E2-related pathologies relies on the modulation of ER trancriptional activity by anti-estrogens; however, data accumulated during the last five years reveal that ER activities are not only restricted to the nucleus. ERs are very mobile proteins continuously shuttling between protein targets located within various cellular compartments (e.g., membrane, nucleus). This allows E2 to generate different and synergic signal transduction pathways (i.e., non-genomic and genomic) which provide plasticity for cell response to E2. Understanding the structural basis and the molecular mechanisms by which ER transduce E2 signals in target cells will allow to create new pharmacologic therapies aimed at the treatment of a variety of human diseases affecting the cardiovascular system, the reproductive system, the skeletal system, the nervous system, the mammary gland, and many others.

Reduced levels of oestrogen receptor beta mRNA in Swedish patients with chronic fatigue syndrome

BACKGROUND

Chronic fatigue syndrome (CFS) is an illness with unknown aetiology and pathophysiology. The difference in incidence by sex observed for CFS indicates a role for oestrogen and oestrogen receptors in disease development. Furthermore, an immunomediated pathogenesis has been suggested for CFS, providing an additional connection to oestrogen, which displays immunomodular functions.

AIMS

To investigate a possible association of oestrogen receptor (ER) mRNAs and two ERbeta single-nucleotide polymorphisms (SNPs) with CFS.

METHODS

Messenger RNA levels of ERalpha, ERbeta wt and ERbeta cx were investigated in peripheral blood mononuclear cells from 30 patients with CFS and 36 healthy controls by quantitative real-time polymerase chain reaction. Two ERbeta SNPs were scored in the same material.

RESULTS

The CFS group showed significantly lower mRNA expression levels of ERbeta wt compared with the healthy control group. No differences were observed for ERalpha or ERbeta cx between patients and controls. There were no significant differences in frequency for the investigated ERbeta SNPs between cases and controls.

CONCLUSIONS

The reduced ERbeta wt expression level observed in this study is consistent with an immune-mediated pathogenesis of CFS. Additionally, the observation that ERbeta wt expression is decreased in CFS could provide an entry point to identify interesting, potentially disease-causing, candidate molecules for further study. A possible connection between oestrogen, oestrogen receptors and CFS should be evaluated further.

Estrogen receptors and human disease

Estrogens influence many physiological processes in mammals, including but not limited to reproduction, cardiovascular health, bone integrity, cognition, and behavior. Given this widespread role for estrogen in human physiology, it is not surprising that estrogen is also implicated in the development or progression of numerous diseases, which include but are not limited to various types of cancer (breast, ovarian, colorectal, prostate, endometrial), osteoporosis, neurodegenerative diseases, cardiovascular disease, insulin resistance, lupus erythematosus, endometriosis, and obesity. In many of these diseases, estrogen mediates its effects through the estrogen receptor (ER), which serves as the basis for many therapeutic interventions. This Review will describe diseases in which estrogen, through the ER, plays a role in the development or severity of disease.

Estrogen-metabolizing gene polymorphisms and lipid levels in women with different hormonal status

Endogenous and exogenous sex steroid hormones have multiple effects on lipid and lipoprotein metabolism. It is also known that estrogen has antiatherogenic actions, therefore we considered examining whether there was any association between polymorphisms in estrogen-metabolizing genes and lipid levels in women. We investigated the association between variants in genes related to estrogen biosynthesis (CYP19-TTTA(n)) and estrogen catabolism (CYP1A1*2A, CYP1A1*2C, CYP1A2-Asn516Asn, CYP3A4*1B, and COMT-Val158Met) with serum lipid levels in a cross-sectional study with 472 Brazilian women of European descent. They were divided into three subgroups according to their hormonal status: premenopausal women (n=187), postmenopausal women exposed to hormonal replacement therapy (HRT) (n=118), and postmenopausal women unexposed to HRT (n=167). The postmenopausal women receiving HRT who were carriers of the CYP3A4*1B variant showed lower low-density lipoprotein cholesterol levels than wild-type homozygotes. Premenopausal women homozygous for the CYP1A1*2C allele had higher high-density lipoprotein cholesterol levels than heterozygotes. While the CYP1A1*2C variant probably has a higher catalytic activity, the functional implications of the CYP3A4 polymorphism are still uncertain. These data are the first attempt to associate estrogen metabolism genes to lipid levels in women.

ESR1 and APOE gene polymorphisms, serum lipids, and hormonal replacement therapy

OBJECTIVES

The risks and benefits of hormone replacement therapy (HRT) are, at least in part, mediated by the metabolic individuality of women. Therefore, we investigated the association between polymorphisms at the estrogen receptor 1 gene (ESR1) and at the apolipoprotein E gene (APOE) with lipid and lipoprotein levels in order to verify whether these concentrations are modulated by these gene variants in women with different hormonal status.

METHODS

One hundred and eighteen postmenopausal women using oral HRT with estrogen or estrogen plus progestagen (HRT+, mean age=56+/-6.7 years, 39-75 years) and 167 postmenopausal women that were not on HRT (HRT-, mean age=58+/-9.8 years, 38-85 years) participated in the study. The polymorphisms were genotyped by PCR-RFLP methods.

RESULTS

No significant effect of ESR1 genotypes or haplotypes and ESR1*HRT interactions were detected on lipid levels in two-way analysis of variance. Postmenopausal women HRT nonusers carriers of the APOE*4 allele had higher T-chol and LDL-C levels than postmenopausal women HRT nonusers carriers of the APOE*3 and APOE*2 allele. T-chol and LDL-C concentrations in postmenopausal users of HRT that were APOE*4 carriers were similar to those in postmenopausal women nonusers of HRT homozygotes for APOE*3 and APOE*2 carriers. A significant APOE*4/HRT interaction was detected on T-chol and LDL-C levels by multiple regression analysis.

CONCLUSION

The results from this study suggest that the HRT influence on T-chol and LDL-C levels is modulated by APOE isoforms but not by ESR1 polymorphisms.